Fluke Victoreen 875 Users Manual 877 1

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Victoreen® 875
High Range Containment Monitor

Operators Manual

February 2005
Manual No. 877-1-1 Rev. 9
©2004, 2005 Fluke Corporation, All rights reserved. Printed in U.S.A.
All product names are trademarks of their respective companies

Fluke Biomedical
Radiation Management Services
6045 Cochran Road
Cleveland, Ohio 44139
440.498.2564
120 Andrews Road
Hicksville, New York 11801
516.870.0100
www.flukebiomedical.com/rms

Table of Contents
Section 1:
1.1
1.2
1.3
1.4
1.5
1.6

Introduction................................................................................................ 1-1
General Description ..................................................................................... 1-1
Specifications............................................................................................... 1-1
Equipment Overview.................................................................................... 1-3
Receiving Inspection.................................................................................... 1-8
Storage ........................................................................................................ 1-9
Procedures, Warnings, and Cautions .......................................................... 1-9

Section 2:
2.1
2.2

Installation.................................................................................................. 2-1
Installation.................................................................................................... 2-1
Cable and Wiring Installation ....................................................................... 2-3

Section 3:
3.1

Operation.................................................................................................... 3-1
Operation ..................................................................................................... 3-1

Section 4:
4.1
4.2

Operation.................................................................................................... 4-1
Functional Description ................................................................................. 4-1
Readout Module 876A-1 .............................................................................. 4-1

Section 5:
5.1
5.2
5.3
5.4
5.5
5.6
5.7
5.8
5.9
5.10
5.11
5.12
5.13
5.14
5.15
5.16

Maintenance, Calibration, and Troubleshooting..................................... 5-1
Maintenance ................................................................................................ 5-1
Calibration.................................................................................................... 5-1
Troubleshooting ........................................................................................... 5-3
Power Supply Measurements ...................................................................... 5-4
Signal Input Circuit....................................................................................... 5-4
Metering Circuit............................................................................................ 5-5
The Alarm Circuits ....................................................................................... 5-5
High Alarm Circuit ........................................................................................ 5-6
Muting Stages of the Alarm Circuits............................................................. 5-6
ESC Board................................................................................................... 5-7
Overall Fail Circuitry Associated with the ECS Test .................................... 5-9
Starting with Pins M and P on the Power Supply Schematic ....................... 5-9
Starting with Terminal H on Relay Driver Board .......................................... 5-9
Provision of Inputs to Terminals M and P on the Power Supply Board........ 5-9
Outputs of U206 Pulse Generator on the ECS Board................................ 5-10
Operation of the Latch Circuit .................................................................... 5-10

Appendix A: Calibration and Test Procedures..............................................................A-1
A.1
Calibration Procedures ................................................................................ A-1
A.2
Test Procedures .......................................................................................... A-1
Appendix B: Cable and Pull Box Procedures................................................................B-1
B.1
Cable and Pull Box Procedures ................................................................... B-1
Appendix C: Applicable Drawings and Bill of Materials...............................................C-1
C.1
Applicable Drawings ....................................................................................C-1
C.2
Bill of Materials ............................................................................................C-3

Introduction
General Description

Section 1

Introduction
1.1 General Description
Containment Monitor 875
NOTE
The 875 Containment Monitor has been qualified
for use in Nuclear Safety related applications.
Qualification Test Reports, 950.301, 950.308A, and
950.310A define the parameters that have been
verified by test and are available for purchase.
Containment Monitor 875 functions as an accident monitor for reactor containments, refer to Figure 1-1. It
consists of the 877-1 Ion Chamber Detector that is located within the reactor containment, and the 876A-1
Readout Module that is contained in a rack in the control room. The readout module contains a power
supply that provides the necessary power both for itself and the detector. The readout module is
connected to the detector by two cables, a coaxial high voltage cable and a coaxial signal cable.
Specifications for the detector and readout module are contained below.

1.2 Specifications
Detector 877-1
Radiation Detected

Photons above 60 keV

Range

1 R/h to 1E7 R/h

Energy Response

± 20% from 80 keV to 2 MeV

Chamber Construction

Stacked parallel plate, 316 stainless steel housing, 3
terminal, guarded ion chamber

Saturation

>80% up to full scale on instrument

Collection Voltage

450 to 550 VDC

Current Output

7E-11 to 7E-4 Amp/R/Hr (nominal)

Chamber Capacitance

435 picofarads (nominal)

Voltage Withstand and Leakage

5E10-5 amperes @ 500 VDC between either ground and
connector pins

Capacitance

Approximately 430 pf

1-1

Victoreen 875
Operators Manual
Hermetic Integrity

1E10-5 cm3 of helium per second @ one standard
atmosphere

Chamber Fill Gas

Nitrogen/helium (2%) at atmospheric pressure

Dimensions (W x H x D) with Mounting Bracket
9.25 x 12.5 x 10.06 in
(234.95 x 317.5 x 255.52 mm)
Weight

Approximately 18 lb (8.17 kg)

Temperature, Storage

40° to 160°F (4° to 71°C)

Temperature, Operating

40° to 160°F (4° to 71°C)
375°F (180°C) peak, accident, 3 hours

Relative Humidity

100% (waterproof)

Total Integrated Dose

2E8 Rads + 10% margin, 60Co

Chemical Spray

0.45 Gallons/minute/ft2 (0.28 molar H3BO3, 3000 ppm
Boron, and NaOH; ph of 11, 24 hrs

LOCA Test Duration

28 days

(Consult Fluke Biomedical, Radiation Management Services, for a complete description of Qualification
Test Results)

Readout Module 876A-1
Range

1 to 107 R/h

Input Current

Minimum: 6.5 to 7.5 x 10-11 A
Maximum: 6.5 to 7.5 x 10-4 A

Recorder Output
optional)

0 to +1 VDC, logarithmic (0 - 10 mV and 0 – 5 V

Computer Output
optional)

0 to +5 VDC, logarithmic (0 - 100 mV and 0 - 50 mV
(Other Outputs Available Upon Request)

System Accuracy (during "all" conditions)

Accumulative @ Meter +36% of input radiation
Analog Outputs +28% of input radiation

Power Requirements:

a) AC Voltage: 108 to 132 VAC, RMS @ 60 ± 3 Hz
b) Battery Power: 22 to 32 VDC @ 600 mA DC

maximum
Temperature Coefficient

0.40%/°C, + 0.25 R/h/°C

Dimensions (W x H x D)

8.46 x 5.25 x 15.21 in
(214.88 x 133.35 x 386.33 mm)

Weight

20 lbs (9.07 kg)

Environmental Parameters

Temperature (Storage): 40° to 140°F (4° to 60°C)
Temperature (Operating): 40° to 120°F (4° to 49°C)

1-2

Introduction
Specifications

Relative Humidity (Storage): 0 to 95% (noncondensation)
Relative Humidity (Operating): 0 to 90% (noncondensation)
Irradiation: 3.5 to 1 x 103 Rads @ 60°C integrated over

40 years life.
Mounting

876-1-55, Rack Chassis

Available Options (consult factory)

876A-100: Readout, for use with digital systems
Outputs:

0 - 100 mV
0 - 50 mV
0 - 10 mV
0- 5V

Figure 1-2 illustrates the typical energy response for the detector, Figure 1-3 illustrates typical linearity for
the detector and Figure 1-4 illustrates radiation input versus meter reading.

1.3 Equipment Overview
High-Range Containment Monitor Detector (877-1)
The high-range containment monitor detector is an ion chamber detector that has the appearance of a
six-inch diameter domed cylinder about seven inches long. Inside the cylinder are two flange-mounted
electrodes consisting of 31 flat, disk-shaped plates, each about four inches in diameter, stacked, and
mounted on disk rods. The assembly has the appearance of a large air capacitor. The mounting posts are
attached to the mounting flange through insulating spacers, so the flange and housing will be neutral with
respect to the charges applied to the electrodes.
The whole assembly is covered by the six-inch diameter housing which contacts only the neutral
mounting flange. The mounting flange is pierced by three holes. One hole supports the exhaust tube used
for exhausting and back filling the chamber. The other two support two 2-pin connectors, one for each
electrode. One pin in each pair is connected to the neutral mounting flange. When the coaxial signal
cable is connected to this connector, the cable shield is connected to the neutral pin.
The entire chamber is filled with a mixture of helium and nitrogen at atmospheric pressure and sealed.
For further information refer to Section 4, Functional Description.

Readout Module (876A-1)
The 876A-1 Readout Module is designed to give an indication, on an analog meter, of radiation levels
within the containment area. The readout is composed of an analog meter, indicator lights and operating
switches. The meter has a range of 1 to 107 R/h and is controlled by an eight position rotary switch. The
readout is mounted in the 876-1-55 Rack Chassis located in the control room.
For further information refer to Section 4, Functional Description.

Rack Chassis (876-1-55)
The 876-1-55 Rack Chassis permits mounting of two readout modules or one readout module and one
optical isolator in a 19-inch wide RETMA equipment rack. The panel height is 5.21 inches.
For further information refer to applicable drawing located in Appendix C.

1-3

Victoreen 875
Operators Manual

Pull Box Assembly (878-12-5)
The 878-12-5 Pull Box Assembly is designed to allow for thermal expansion of the detector cables and to
provide a service loop. Various optional pull-box configurations are available per Table 1-1. For more
information refer to Section 2, Appendix B, and Appendix C.

Table 1-1.

Pull-box Variations

Model

Inlet, Size and Location

878-12
878-12-M 1
878-12-M2
878-12-M3
878-12-M4
878-12-M5
878-12-M6
878-12-M7
878-12-M8
878-12-M9

1" 270°
1" MNPT 270°
1" MNPT 270°
1" 270°
1" 270°
¾" 270°
2, ¾" 0°/360°
1" MNPT 270°
2, ¾", 0°
1,1" MNPT 90°

878-12-M10
878-12-M11
878-12-M12

1,1" MNPT
2, ¾", 90°
2, ¾", 270°

Outlet, Size and
Location
2, ¾", 90°
2, ¾", 90°
2, 1", 90°
1, 1", 90°
1, 1", 90°
2, ¾", 90
2, ¾", 90
2, ¾", 90
1,1", MNPT, 90°
1, ¾" MNPT, 120°
1, ½" MNPT, 210°
2, ¾ 90°
1,1" MNPT 90°
1" MNPT, 0°

Inlet/Outlet Orientation
180°
180°
180°
180°
90°
180°
90°
90°
90°
150°
210°
0°
0°
90°

Flexible Tubing (878-12-30TAB)
1.0 inch diameter flexible stainless steel tubing is available in various lengths to interconnect the 877-1
Detector to the first pull-box.

Cables/Connectors/Panel
In-Containment Cable: (878-1-9-TAB)
Ex-Containment Cable: (50-103-TAB)
Replacement Detector Connector Kit: (878-7-5)
Blank Panel: (844-8-5)

Optional Equipment
The following optional equipment is available:
878-10

1-4

Field Calibrator - 250 mCi 137Cs

Introduction
Equipment Overview

Figure 1-1. High-Range Containment Monitor 875

1-5

Victoreen 875
Operators Manual

Figure 1-2. Typical Energy Response Curve – Detector 877-1

1-6

Introduction
Equipment Overview

Figure 1-3. Typical Linearity Detector 877-1

Figure 1-4. Radiation Input vs. Meter Reading (Calculated Curve)

1-7

Victoreen 875
Operators Manual

Figure 1-5. High-Range Detector, Recommended Installation

1.4 Receiving Inspection
Upon receipt of the unit:
1. Inspect the carton(s) and contents for damage. If damage is evident, file a claim with the carrier and
notify Fluke Biomedical, Radiation Management Services at 440.248.9300.
2. Remove the contents from the packing material.
3. Verify that all items listed on the packing list have been received and are in good condition.

NOTE
If any of the listed items are missing or damaged,
notify Fluke Biomedical.

1-8

Introduction
Storage

1.5 Storage
Storage of Victoreen instruments must comply with level B storage requirements as outlined in ANSI
N45.2.2 (1972) Section 6.1.2(.2). The storage area shall comply with ANSI N45.2.2 (1972) Section 6.2
Storage Area, paragraphs 6.2.1 through 6.2.5. Housekeeping shall conform to ANSI N45.2.3 (1972).
Level B components shall be stored within a fire resistant, tear resistant, weather tight enclosure in a wellventilated building.
Storage of Victoreen instruments must comply with the following:
1. Inspection and examination of items in storage must be in accordance with ANSI N45.2.2 (1972)
Section 6.4.1.
2. Requirements for proper storage must be documented and written procedures or instructions must
be established.
3. In the event of fire, post-fire evaluation must be in accordance with ANSI N45.2.2 (1972), Section
6.4.3.

4. Removal of items from storage must be in accordance with ANSI N45.2.2 (1972), Sections 6.5 and
6.6.

1.6 Procedures, Warnings, and Cautions
The equipment described in this manual is intended to be used for the detection and measurement of
ionizing radiation. It should be used only by persons who have been trained in the proper interpretation of
its readings and the appropriate safety procedures to be followed in the presence of radiation.
Although the equipment described in this manual is designed and manufactured in compliance with all
applicable safety standards, certain hazards are inherent in the use of electronic and radiometric
equipment.
WARNINGS and CAUTIONS are presented throughout this document to alert the user to potentially
hazardous situations. A WARNING is a precautionary message preceding an operation that has the
potential to cause personal injury or death. A CAUTION is a precautionary message preceding an
operation that has the potential to cause permanent damage to the equipment and/or loss of data.
Failure to comply with WARNINGS and CAUTIONS is at the user's own risk and is sufficient cause to
terminate the warranty agreement between Fluke Biomedical and the customer.
Adequate warnings are included in this manual and on the product itself to cover hazards that may be
encountered in normal use and servicing of this equipment. No other procedures are warranted by Fluke
Biomedical. It shall be the owner’s or user's responsibility to see to it that the procedures described here
are meticulously followed, and especially that WARNINGS and CAUTIONS are heeded. Failure on the
part of the owner or user in any way to follow the prescribed procedures shall absolve Fluke Biomedical
and its agents from any resulting liability.
Indicated battery and other operational tests must be performed prior to each use to assure that the
instrument is functioning properly. If applicable, failure to conduct periodic performance tests in
accordance with ANSI N323-1978 (R1983) Radiation Protection Instrumentation Test and Calibration,
paragraphs 4.6 and 5.4, and to keep records thereof in accordance with paragraph 4.5 of the same
standard, could result in erroneous readings or potential danger. ANSI N323-1978 becomes, by this
reference, a part of this operating procedure.

1-9

Victoreen 875
Operators Manual
(Blank page)

Installation
Installation

Section 2

Installation
2.1 Installation
Installation of the monitoring system consists of selecting suitable mounting sites for each component of
the system, mounting each of the components, and connecting the components into the system
configuration.
Installation of this system is as follows:

NOTE
Refer to the applicable drawings in Appendix C for
further installation Instructions.
Rack Chassis
The 876-1-55 Rack Chassis is a standard 19-inch chassis with a flame barrier. When seismic qualification
is required for the readout, seismic support brackets (P/N 876-1-114) are needed to support the rear of
the rack chassis. The brackets are designed to mount on the 19-inch qualified equipment rack.
Recommended mounting is shown on drawings GEL876-1-55, and 876-1-114.

Readout Module
Readout Module 876A-1 is designed to fit into one-half of an 876-1-55 Rack Chassis. Insert the readout
module in the rack chassis (see drawing GEL876A-1), then insert and tighten the two holding screws in
the rear flanges of the rack chassis. The pawl fastener on the front panel of the readout must be
tightened.

Optical Isolator (No longer manufactured, consult factory)
Detector
NOTE
The detector case MUST BE PHYSICALLY
GROUNDED TO EARTH GROUND. The readout
instrument circuit common SHOULD NOT be
grounded to earth ground.
The 877-1 Detector is designed to mount on the containment wall. A mounting bracket attached to the
detector has four holes that are used for mounting. Studs must be placed in the containment wall before
mounting the detector. Dimensions for the studs are the same as the dimensions of the holes in the
mounting bracket (refer to drawing GEL877-1). Recommended studs are 5/16 inch Grade 5. No lock
washers are to be used and recommended torque for the nuts is 18 ft. lbs. Orient the detector so that the
cable connectors are on the underside. Attach the detector to the mounting bracket with the four clamps
provided, securing the bolts with a torque of 132 in. lbs. (Figure 1-5 and GEL877-1).

Pull Box
A cable pull box is required to allow for thermal expansion of the detector cables and to provide a service
loop. The pull box (drawing 878-12-5) is a typical type that mounts to the containment wall. It should be
mounted directly below the detector as shown in Figure 1-1. Depending on actual detector location, more
than one pull box may be necessary.

2-1

Victoreen 875
Operators Manual

NOTE
Under potential L.O.C.A. conditions of pressure and
temperature, the cable may expand as much as 11
inches per 100 feet.
The distance from the pull box to the detector will be determined by the amount of flex hose used to seal
the detector cables. Additional information is found in the paragraph below Cable Sealing and in CABLE877 and 878-12-3 procedures in Appendix B.
Once the cables have been pulled and tested, the pull box cover must be bolted shut. To bolt the pull box
shut, follow the steps outlined in procedure 878-12-3 in Appendix B. Pull box material type and grade is
304 stainless steel.

Cable Sealing
In-containment cable is 878-1-9. This is special cable designed to withstand the potential high radiation
that may exist following a L.O.C.A. or similar event. In order to withstand the high pressure and moisture
generated during such an event, the entire cable length must be sealed so that moisture will not come in
contact with the cable. Cable specifications are listed below.
Specifications for Cable 878-1-9
Conductor

#24 AWG, 19/36 Tinned Copper

Insulation

Tefzel (BIWF)

Shield

#36 AWG, Tinned copper brand, 90% Coverage

Jacket

Tefzel (BIWF)

Outside Diameter

0.250 to 0.295 in
(6.35 to 7.49 mm)

Impedance

75 ohms nominal

Capacitance

22 pf/ft nominal

Dielectric Strength

7000 V minimum

Operating Voltage

2300 V maximum

The following guidelines are based on the sealing method used during the qualification test. Stainless
steel Flex Hose 878-12-30, ¾ inch diameter x 18.5 inches long (with welded Swagelok connectors)
should be installed between the detector and pull box. Stainless steel tubing (¾ inch diameter) should be
installed from the pull box to the penetration for each cable. If a common stainless steel tubing run is
used, a one (1) inch diameter tube is recommended.

NOTE
Seismic support and the sealing technique at
penetration vary with plant requirements.
Techniques and materials used are the customer's
responsibility.
Attach the stainless steel tubing to the pull box with compression fittings (¾ inch) and, after finger
tightening, tighten at least 1-¼ turns. The flex hose connection at the pull box is installed in the same
manner. The detector end of the flex hose is swaged to the cable connector backshell. This should not be

2-2

Installation
Installation

done until cable is pulled and tested. (Refer to the procedure Cable-877, in Appendix B, for more
information.)

NOTE
Minimum bend radius of the 878-1-9 cable is four
inches. When bending conduit or flex hose, take
this into consideration. Typical bend radius for P/N
878-12-30 is ¾ inch; stainless steel flex house is 12
inches.

2.2 Cable and Wiring Installation
Detector Cable Inside Containment
Detector cables used inside containment are to be installed and terminated according to procedure
Cable-877, in Appendix B. Do not allow any moisture or contaminants to deposit on the connectors used
for installing cables due to the potential for electrical leakage. Because the detector transmits extremely
small current signals, no terminal block connections are acceptable in the penetration. Signal conductor
must be shielded but not grounded (qualified butt splices are acceptable). Refer to drawing GEL875-1 for
electrical connections and to 878-1-9 for cable data.

CAUTION
The detector and readout must not be connected
during the following test.
Detector Test After Installation
Testing of detector cables after installation is required. A leakage test from the center conductor to the
shield should yield better than 1000 megohms at 1000 VDC.
Typical resistance of the center conductor is 0.022 ohm per foot at 20°C (68°F).

Detector Cable Outside Containment
Detector cables used outside containment should be a qualified coaxial type RG 59/U. Ideally, the cable
should connect directly from the penetration to the appropriate connectors on Readout Module 876A-1.
Terminal block connections and unshielded center conductors are not acceptable for installation. Fluke
Biomedical recommends that cable 50-103 be used. Typical wiring is shown on drawing GEL 875-1. After
installation, testing is required as described in the previous paragraph. Specifications for cable used
outside containment are listed below. Refer to drawing 50-103 for additional data.

Specifications for Cable 50-103
Type

RG 59/U, alternate

Conductor

19/36 Tinned copper

Insulation

Cross-linked polyethylene

Flame Tape

Mica tape

Shield

#36 AWG, 92% coverage

Insulation Wrap

0.001 inch (0.03 mm) mylar

Jacket Type

Bostrad 7 (CSPE)

2-3

Victoreen 875
Operators Manual
Thickness

0.015 inch (0.38 mm) nominal

Outer Diameter

0.217 inch (5.51 mm) nominal

Impedance

75 ohms nominal

Capacitance

22 pf/ft nominal

Ancillary Wiring
Ancillary wiring for computer, recorder, power and alarm contacts are installed according to drawing GEL
875-1 and Table 2-1 which indicates connector pin designations.

Table 2-1.

Alert Alarm I

Alert Alarm II

High Alarm I

High Alarm II

Fail Alarm I

Fail Alarm II

Installation
Computer & Recorder
Function
Ground
Ground
Computer
Recorder
All Alarms on P2
Normal Operation *
N
NO
P
C
R
NC
D
NO
E
C
F
NC
S
NO
T
C
U
NC
G
NO
H
C
J
NC
K
NO
L
C
M
NC
A
NO
B
C
C
NC
Power Connections (P1)
Line
Neutral
Chassis Ground

J3
D
F
E
C
Shelf State
NC
C
NO
NC
C
NO
NC
C
NO
NC
C
NO
NC
C
NO
NC
C
NO
A
B
C

* Relays are Fail Safe, i.e. energized for normal operation. Relays de-energize during an alarm condition.
NO = Normally open
C = Common
NC = Normally closed

2-4

Operation
Operation

Section 3

Operation
3.1 Operation
Once installation is completed, operation is fully automatic. The 876A-1 Readout Module continuously
indicates the level of radioactivity measured at the detector site. When the radiation level exceeds an
alarm set point, an alarm is actuated.
The following steps explain how to operate the 875 monitor:
1. Turn the function switch to the TEST position, and press and release the Electronic Check Source
(ECS) push button. About four seconds later, the SAFE-RESET light should come on. Then press
and hold the CHANNEL TEST push button. The ALERT, HIGH, and CHANNEL TEST lamps should
light immediately.

NOTE
When channel test is pressed, the high and alert
alarm relays are deactivated. (Their coils are deenergized). The wiring of the channel test circuit is
such that the channel test lamp will not light unless
the alarm relay contacts are in the deactivated or
tripped state. This is for the purpose of assuring
that an actual contact state change has occurred,
identifying that the channel is in the test mode.
Reconciling these alarm conditions is the user's
responsibility, since the remote alarms are not
included in the standard containment monitor
system.
2. Release the CHANNEL TEST push button. The SAFE-RESET lamp should stay on. Either or both
of the HIGH (red) and ALERT (yellow) lamps may stay on or go out depending on the alarm reset
mode chosen by the installation of jumpers on the alarm circuit board. The monitor is supplied with
the manual reset mode selected.
3. To reset any alarm light, press the SAFE-RESET push button. If conditions are normal, the light will
go out.
4. Switch the function switch to the ALL position.
5. Again press the ECS push button. The panel meter indicator should go to a reading of about 103
R/h and the green SAFE-RESET light stays on in the operating condition. If the panel meter shows
little or no deflection at the pressing of the ECS push button, the green light should go out four
seconds after the ECS push button is pressed. In this case, follow troubleshooting procedures.
6. To set the alert and high alarm adjustments, remove two screws in the rear of the chassis, loosen
the knurled knob on the front of the chassis, and slide the module forward part way out of the rack
to reveal the adjustment potentiometers R513 and R509 on the relay driver printed circuit board. To
adjust the HIGH alarm, depress the red HIGH push button and adjust R513 (drawing 876A-1-75A)
until the meter indicates the desired alarm level. To adjust the ALERT alarm, depress the yellow
ALERT push button and adjust R509 (drawing 876A-1-75A) until the meter indicates the desired

3-1

Victoreen 875
Operators Manual
alarm level. Return the module to its proper position in the rack. Tighten the rear holding screws.
Tighten the knurled holding knob on the front. Return the module to service.
During normal operation, the radiation field is usually less than 1 R/h (the lower limit of detection of the
high range detector) and the analog meter display will be at the low end of the meter scale.

Figure 3-1. Readout Module 876A-1, Front and Rear View (reference only, not to scale)

3-2

Function Description
Functional Description

Section 4

Function Description
4.1 Functional Description
High-Range Containment Monitor Detector 877-1
The high-range containment monitor detector is an ion chamber detector that has the appearance of a
six-inch diameter domed cylinder about seven inches long, mounted on an L shaped bracket. Inside the
cylinder are two flange-mounted electrodes consisting of 31 flat, disk-shaped plates, each about four
inches in diameter, stacked, and mounted on disk rods. The 31 disks form two groups, interleaved with
each other, 16 collection disks and 15 signal disks. Because of the interleaving, they appear as only one
stack, but the collection disks are mounted on three collection disk-posts and the signal disks on three
signal disk-posts. Spacers on the posts keep the disks separated so they do not come in contact, and
clearance holes in the disks allow posts of the opposite polarity to pass through without contact. The
assembly has the appearance of a large air capacitor. The mounting posts are attached to the mounting
flange through insulating spacers, so the flange and housing will be neutral with respect to the charges
applied to the electrodes. The collecting diskposts are elongated beyond the last collecting disk to support
a cup-shaped liner having the same potential as the collecting disks, thus becoming part of the collector.
The whole assembly is covered by the six-inch diameter housing which contacts only the neutral
mounting flange. The mounting flange is pierced by three holes. One hole supports the exhaust tube used
for exhausting and back filling the chamber. The other two support two 2-pin connectors, one for each
electrode. One pin in each pair is connected to the neutral mounting flange. When the coaxial signal
cable is connected to this connector, the cable shield is connected to the neutral pin.
The entire chamber is filled with a mixture of helium (2%) and nitrogen at atmospheric pressure and
sealed.

CAUTION
The seal on this chamber must not be broken. To
do so would alter the calibration and specified
energy response of the system.

4.2 Readout Module 876A-1
NOTE
Drawings 876A-1-3H and 876-1-3A serve as
interconnecting diagrams for tracing signals
between printed circuit boards. In addition, drawing
876-1-3A contains the main power supply

4-1

Victoreen 875
Operators Manual

PreamplifierIMeter Printed Circuit Board (P/N 876A-1-86, Schematic 876A-1-3E)
The detector current, measuring from 7 x 10-11 to 7 x 10-4 amperes respectively, at the bottom and top of
the reading range, enters the readout on rear panel connector J1. From the rear panel, the ion chamber
current enters the preamplifier circuit through terminal J302. It passes to U301, a seven-decade
logarithmic amplifier, where it produces an output voltage of 5 V for minimum currents and -2.6 V for
maximum currents. This voltage can be monitored at TP501, on the relay driver PC Board.
Q301A and Q301B have their bases connected to their collectors, so that they operate as diodes. Q301
limits over-range inputs to U301. Q302A is a lower-level clamp on the input to logarithmic amplifier U301,
keeping the current from falling below 1 % of the lower limit of sensitivity. This limiting of the low level
current speeds the response of the logarithmic amplifier. The output of U301appears on terminal 13 of
J301. This terminal is connected to terminal 13 of J103 on the motherboard by a ribbon cable. From this
point, connection is made to terminal 14, J106 of the relay driver printed circuit board. This terminal is
effectively the point of input to the meter circuit and high and alert alarm circuits.
Amplifier and meter circuits can be tested by turning the function switch to TEST and depressing the
CHANNEL TEST push button on the front panel. This applies 15 volts to a circuit of which Q302B is a
series element; the purpose is to generate an input current for U301 (at pin 2) such that panel meter
M401 will be driven full scale.
Panel meter M401 may be switched into anyone of six positions of different sensitivity. The meter current
is determined by the voltage applied to pin 10 of U401 from pin 3 of J401. U401 is driven in turn by U501
of the relay driver printed circuit board. Connection is made from terminal 12 of the relay driver printed
circuit board to terminal 3, J401 of the preamplifier metering printed circuit board through pins 11 and 14,
J101 of the switchboard (drawing 876-1-3J) so that the signal path may be interrupted when it is desired
to use the meter for alarm setpoint checks.
One of the six sensitivity positions, the ALL position, displays all seven decades on the red meter scale.
Each of the other positions expands the scale to achieve a three-decade display on the black scale. In
addition there is a TEST position and an OFF position. The TEST position is also a seven-decade meter.

Power Supplies
Mother Board Power Supplies (P/N 876-1-78, Schematic 876-1-3A)
T101 acts as a step down transformer producing an output voltage of 24 VDC. This is rectified in the fullwave rectifier consisting of four diodes, CR101 through CR104. The 0.1 microfarad capacitors on the AC
input suppress spikes and limit noise. The output of this 24-volt supply provides the power to both the
positive and negative power supplies on the power supply printed circuit board.

Printed Circuit Board Power Supplies (P/N 876-1-89, Schematic 876-1-3C) (P/N 876-1-89A,
Schematic 876-1-93A)
Positive Power Supply
Twenty-four (24) V power from the motherboard enters the power supply board on terminal 1. Integrated
circuit U2 is a voltage regulator; +15 V comes out of pin 2 of U2. A second supply of +14 volts is provided
through pass element Q1. This output serves relays, lights, and other high current circuit elements. It is
current-limited through R29. The 14 V supply is monitored at TP3.

Negative Power Supply
Transistors Q7 and Q8 make up a free-running multivibrator with a 9 kHz repetition rate, which is powered
by the unregulated 24 volts from the motherboard power supply. Q6 acts as a current limiter for this
multivibrator. U1, pins 8, 9, and 10, and Q5 accept its output and act as a driver stage for the rectifier
which follows. This rectifier consists of CR4 and CR5, and produces a negative voltage, which should be
about -21 VAC, and can be measured at TP5. Voltage regulator U1 (located on the 876-1-89A add-on PC
board) takes this voltage as an input, and delivers a -10 V regulated voltage, which is obtained from
terminal K of the board, and can be monitored at TP4.

4-2

Function Description
Readout Module876A-1

High Voltage Power Supply Normal Operation (non-ECS Test)
The multivibrator circuit of Q7 and Q8 also supplies the input to the high voltage generator. Two of the
transistors of U1 act as buffers between the multivibrator and the high voltage circuit. Q4 and Q3 serve an
output driving stage for the primary of high voltage transformer T1. The input to T1 is a square wave,
approximately 12.5 V peak to peak. T1 has a step-up ratio of approximately 20: 1. C22, CR15, CR14, and
C20 form a voltage doubler that gives a DC output of approximately 525 volts. The resistor capacitor
circuit R42, R43, and R44, and C17, C18, and C19 serve for further filtering, and ultimately a 506 volt
output is delivered at J1.
R37, R40 and R41 form a voltage divider across the 515 V input to the resistor capacitor filter. The
voltage at the junction of R37 and R40 is the input to OP AMP U2 pins 6 through series resistor R39. Pins
5 and 6 of U2 are the inputs to a difference amplifier, which acts to produce additional regulation of the
high voltage.
U2 (pins 1, 2, 3) is used as a logic circuit in the SAFE/FAIL circuit of the monitor, refer to FAIL/SAFE
Comparison Circuit on Power Supply Board for additional information. In addition to the 6.2 V
reference signal, a voltage will be present at terminal P that comes from terminal 8 of the ECS board
during the ECS test, and a muting signal will also be present at terminal M. This circuit is a part of a
complex checking circuit during the ECS test, and is described in more detail in the "FAIL/SAFE"
paragraph.

Operation of High Voltage Supply During ECS Test
A low voltage ramp (approximately 0 to 6.2 V) from the ECS board enters the power supply board on
terminal 12, and proceeds through a series of auxiliary circuits to give a ramp of the same waveshape on
the center-tap of the primary of high voltage transformer T1, which point is also the source of power to the
driving circuit Q3 and Q4. As a result of this variation of the voltage at the center-tap, the amplitude of the
current in the primary varies accordingly, and ultimately the voltage output at J1 varies from 0 to 506
volts, linearly with time. This high voltage ramp generates the current in the detector circuit during the
ECS test period.

FAIL/SAFE Comparison Circuit on Power Supply Board
The comparison circuit on the power supply board, consisting of U2, pins 1, 2, and 3 has two functions:
The first function, a monitoring of the high voltage, is in operation at all times except during the ECS test.
If this voltage falls below 80% of its rated value, (roughly, from 500 to 400 volts), the FAIL/SAFE circuit
will go out, and the FAIL relay will de-energize. During this period, a steady 6.2 volts, which is input on
terminal 13, serves as a comparison voltage. The voltage on pin 2 is proportional to the high voltage
through a high ratio voltage divider.
The second function, a monitoring of the result of the ECS test, is in operation during this test. During this
period, the high voltage falls well below 400 volts (actually, practically to zero) so the monitoring of the
high voltage as in the above paragraph is inapplicable. Instead, the following are the input and output
conditions.
On pin 2 there is impressed a positive 15-volt signal that lasts for the duration of the ECS test (6.0
seconds). The voltage on terminal M is 15 volts during the ECS test and zero at all other times. The wave
shape that creates this condition on terminal M is called the muting signal wave shape. It will override
whatever voltage would otherwise be present through the high ratio voltage divider from J1.
On pin 3 of the comparison circuit there is impressed a DC voltage that is either 6.2 volts (safe condition)
or 15 volts (fail condition). This voltage arrives on terminal P of the power supply board from a latch circuit
on the ECS board, which circuit will be described in connection with that board. A safe condition causes
the output on terminal N (from pin 1 of U2) to be -10 volts; a fail condition causes it to be +15 volts.
Terminal N is connected to the SAFE/FAIL circuit on the relay driver board, which controls the action of
the fail relay and the SAFE-RESET green lamp on the panel. A fail condition causes the green lamp to go
out and de-energizes the fail relay, although the muting signal delays these actions until the end of the six
(6) second ECS test period. For the safe condition the green light is on, and the fail relay is energized.

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Victoreen 875
Operators Manual

PreamplifierIMeter Board Power Supply (P/N 876-1-86, Schematic 876-1-3E)
A +6.2 V power supply contained on the preamplifier meter board has as its input the +15 V from the
power supply board. Integrated circuit U401, pins 12, 13, and 14 is a voltage regulator with diode U402
providing a stable reference voltage. The output is adjustable by R413.

Relay Driver Printed Circuit Board (P/N 876A-1-75A, Schematic 876A-1-3B)
The signal input to the relay driver printed circuit board which is taken from pin 13 of the preamplifier
meter may be monitored at this point through test point TP501. The signal enters pin 13 of OP AMP
U501, and the output is taken from pin 14. The gain of this amplifier stage can be adjusted by
potentiometer R503. The output of the OP AMP can be monitored at TP502; it provides inputs to:
•

High Alarm circuit

•

Alert Alarm circuit

•

Meter buffer amplifier circuit

•

Recorder/Computer drivers

High Alarm Circuit
The signal output to the high alarm circuit enter OP AMP U502 on pin 5. This is a difference amplifier,
whose other input (pin 6) is determined by the setting of potentiometer R513. The main purpose of this
stage is to control the high alarm threshold.
The output of the comparison OP AMP is connected, through diode CR504, to pin 6 of U503, which acts
mainly as a power stage for the HIGH ALARM (red) panel light. The output of this stage (pin 7) also
serves as the input to the high alarm relay driver stage U503, whose main function is to drive relay K502.
The input to the high alarm relay driver stage of U503 is on pin 9, and the output is taken from pin 8.
Relay K502 is energized in the non-alarm state, and a signal above threshold serves to de-energize it.
There is a red HIGH ALARM jumper connected to the collector (pin 8) of the relay driver U503. The
following options are available with the presence or absence of the jumper when the radiation level
exceeds the threshold and triggers the alarm:
Manual Reset - The alarm will continue to be activated even after the radiation level recedes below
threshold until the SAFE/RESET indicator push button on the panel is depressed. This option occurs
with the jumper in place.
Automatic Reset - The alarm will continue to be activated only as long as the radiation exceeds the
threshold level. This option occurs with the jumper removed.
The red warning light acts similarly to the alarms. It lights when the alarm relay is de-energized.
Each relay contains four Form C contacts, but only two of the four are accessible through the rear
connector.
The connection to the red panel warning light is from terminal 3 of the printed circuit board, which is
connected to the collector (pin 7) of U503 through resistor R521.

Alert Alarm Circuit
The signal input to the alert alarm circuit enters OP AMP U502 on pin 3. This is a difference amplifier,
whose other input (pin 2) is determined by the setting of potentiometer R509. The main purpose of this
stage is to control the alert alarm threshold. The output of the comparison OP AMP is connected, through
diode CR501, to pin 13 of U503, which acts mainly as a power stage for the Alert (yellow) panel light. The
output of this stage (pin 14) also serves as the input to the alert alarm relay driver stage U503, whose
main function is to drive relay K501. The input to the alert alarm relay driver stage of U503 is on pin 2,
and the output to the relay is taken from pin 1. Relay K501 is energized in the non-alarm state, and a
signal above threshold serves to de-energize it.

4-4

Function Description
Readout Module876A-1

There is a yellow ALERT ALARM jumper connected to the collector (pin 1) of the alert alarm relay driver
stage of U503. The following options are available with the presence or absence of the jumper when the
radiation level exceeds the threshold and triggers the alarm:
Manual Reset - The alarm will continue to be activated even after the radiation level recedes below
threshold until the SAE/RESET indicator push button on the panel is depressed. This action occurs with
the jumper in place.
Automatic Reset - The alarm will continue to be activated only as long as the radiation exceeds the
threshold level. This action occurs with the jumper removed.
The yellow warning light acts similarly to the alarms. It lights when the alarm relay is de-energized.
Each relay contains four Form C contacts, but only two of them are accessible from the rear connector.
The connection to the yellow panel warning light is from terminal 2 of the printed circuit board, which is
connected to the collector (pin 14) of U503 through R526.

Fail/Safe Circuit
Input to the fail/safe circuit comes from pin 1 of U2 on the power supply board, entering the relay driver
board on pin H of the relay driver printed circuit board. The input is a DC voltage that is either high (15 V)
or low (0 V); if it is low, relay K3 is energized (non-alarm condition). If the signal is high, the green
SAFE/RESET lamp will go off and the relay is de-energized, indicating a fault somewhere in the system.
The circuit consists basically of two inverters in tandem so the voltage on the collector of Q502 is
approximately the same as the input voltage, the diode CR508 preventing current flow through the
solenoid if the collector is slightly higher than the 14 V at the other end of the solenoid coil.

Recorders and Computer Buffers
Provisions have been made for delivering DC output voltages to a recorder and computer for further
processing. The buffers are located on the relay driver board. If a commercial device is to be connected, a
signal isolator must be installed between the device and the 876A-1 Readout Module output. Inputs to
both computer and recorder buffers arrive at pin R of the relay driver printed circuit board, coming from
terminal 3 on the ECS printed circuit board. The computer buffer consists of and OP AMP using pins 1, 2
and 3 of U501, the output being taken off the relay driver board at pins 4 (+) and 2 (-) of P502. Resistors
R532 and R533 act as voltage dividers for the output. Their values for standard usage and available
options are shown in Table 4-1.
The recorder buffer consists of an OP AMP using pins 5, 6 and 7 of U501, the output being taken off the
relay driver board at pins 1 (+) and 3 (-) of P502. Resistors R530 and R531 act as voltage dividers for the
output. Their value for standard usage and available options are shown in Table 4-1. Both buffers are
disabled during the ECS test by a switching circuit on the ECS board, so that the ECS current is not
recorded. This circuit consists of Q201 and Q202 on the ECS board and is activated by a muting voltage
during the ECS test.

Table 4-1.

Resistance Options for Voltage Dividers

Resistor
Recorder
Voltage
R530
R531
Computer
Voltage
R532
R533

Std.

Option 1

Option 2

Option 3

0–1V

0 – 10 mV

0–5V

0 – 5V

1 kilohm
200 ohms

119.8 kilohms
200 ohms

200 ohms
1 kilohm

0–5V

1 – 100 mV

0 – 50 mV

0–5V

200 ohms
1 kilohm

11.8 kilohms
200 ohms

23.8 kilohms
200 ohms

200 ohms
1 kilohm

Pen Clamp

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Victoreen 875
Operators Manual

The pen clamp circuit is a clamping circuit consisting of U501, pins 8, 9 and 10 and diode CR502. It
prevents pin 9 from going negative. The purpose of this is to prevent the recorder pen from being jammed
against the baseline.

Electronic Check Source (ECS) Printed Circuit Board (P/N 876A-1-92, Schematic 876A-130)
Due to the range of the detector (1 to 10E7 R/h), a remotely activated radioactive check source is
impractical, since the source activity would be high and the shielding necessary for this source would
effect detector energy response. For this reason, an electronic check source is provided. During check
source operation, the detector remains connected to the system as a passive capacitive element. Since
the current-voltage relation in a capacitor is such that the current is proportional to the rate of change of
the applied voltage, an applied voltage, in the form of a linear ramp, will produce a steady current. It is this
current which is read during the ECS test.
The ECS board (drawing 876A-1-3D) has two main functions: 1. To generate the low voltage ramp which,
in the high voltage supply, develops the high voltage ramp responsible for the test current in the detector
during the ECS test. 2. To monitor the current flowing during the ECS test, and recognize whether the test
signifies a passing of failing condition in the circuits of the unit. One of the circuits involved in this
monitoring process is actually on the power supply printed circuit board.
The voltage ramp which develops the detector current during the ECS test rises from 0 to 506 volts over
three seconds, so that the rate of change of voltage is approximately 170 V/second. The capacitance of
the detector is approximately 435 picofarads and therefore, the steady current during the rise of the
voltage ramp is approximately 7 x 10-8 amperes, which puts the panel meter at about one-third full scale.
The ramp occurs when ECS is initiated for a period of about six (6) seconds, during which time the
system is not acting as a radiation monitor.
The ECS test may be initiated at the will of the operator. For this purpose there is a manually operated
ECS push button. If the ECS test is not initiated by the operator, it will take place automatically every 17.1
minutes. After each manually initiated test, the automatic circuits are reset so that a test will be initiated
17.1 minutes later.
In addition to causing visual alarms and relay de-energizing if circuit failures are found, the ECS test
affects the panel meter as in the three cases described below. It is the processing of the voltage read by
the panel meter during the ECS test that is responsible for the action of the circuits directly involved in
driving the visual (green light) and relay (fail) alarm circuits. Recorder and computer outputs are muted
during the ECS and will indicate zero while the test is in progress, approximately six (6) seconds.

Panel Meter Action During ECS Test
The meter action to be expected during the test period with the containment monitor operating properly
can best be explained by considering three initial conditions: 1) Panel meter is resting at extreme lower
end of scale; 2) Panel meter on scale but below 103 R/h; 3) Meter above 103 R/h at start of test.
1. Meter at extreme lower end of scale
In this case, the meter needle should remain motionless for about 1 second, rise to 103 R/h and
remain there for about three seconds, and then fall to its initial position.
2. Meter on scale, but below 103 R/h
In this case, the meter needle should fall to zero at the beginning of the test period. It will then rise
to approximately one-third full scale, and remain in this position for about four seconds. After this, it
will resume its original reading, with perhaps some slight negative overshoot.
3. Meter above 103 R/h at start of test
This case is quite similar to the above except that the meter may not fall to zero at the start of the
test, and at the upswing, it will take a position higher than 103 R/h, the excess depending on the
ambient radiation. It will ultimately resume the same position as before the test as in item 2 above.

4-6

Function Description
Readout Module876A-1

NOTE
During the ECS test, all alarms are muted; that is,
their operation is disabled until the completion of
the test. During this six-second period there is no
warning of a high radiation condition. If this
situation is not tolerable, two containment monitors
must be installed.
Action of Green Safe/Reset Light and Alarm During ECS Test
The behavior of the green SAFE/RESET panel light during the test is as follows:
A pass condition is indicated by the green light remaining lighted throughout the test.
A fail condition is indicated if the green light goes out at the end of the test.

Circuit Actions at Manual and Automatic Initiation of ECS Test
Whether the ECS test is initiated automatically or at the will of the operator, a trigger signal is delivered to
pin 4 (manual) or pin 5 (automatic) of U206, whose output initiates the low voltage ramp generation.
Automatic operation may be disabled by the removal of jumper 200A. The system will then respond only
to the pressing of the ECS button.
The circuit containing U201 (pins 5, 6, 7) and U208 (pins 11 and 12) constitutes a clock with a 0.976
millisecond repetition rate. It is followed by counters U204 and U205. The action of U204 is entirely
restricted to automatic control of the ECS test, as is the output from pin 1 of U205 (note that it may be
open-circuited by the removal of jumper 200A). However, the outputs from pins 3, 5, and 6 have functions
that enter into both manual and automatic action. In addition, they involve both the ramp-generation and
monitoring functions of the ECS board, and also enter into the operation of two important auxiliary
functions: 1) generation of a muting pulse, so that the alarms will not be set off during the ECS test and;
2) re-initiation prevention--that is the prevention of malfunction on manual operation in case the operator
inadvertently presses the ECS button more than once. The monitoring function is involved because the
instant of generation of the latch-enable pulse occurs a precise time after the pressing of the ECS button
initiates the test (toward the end of the test, when conditions have stabilized). The path from U205 pin 6
to the latch-enable generator may be seen to involve the following points: 1) pin 10, U203; 2) pin 5, U207
(input); 3) pin 6, U207 (output) and finally pin 11, U207, whose output drives the latch-enable generator
Q205. The latch and latch enable functions will be explained with the monitoring circuits after the
explanation of the ramp generation.

Low Voltage Ramp Generator
The elements that enter the generation of the low voltage ramp are U203, U208, U201, Q204, and
associated capacitors, resistors, and diodes. U203 is an auxiliary element.
At the arrival of the trigger, Q204 serves the purpose of reducing the voltage previously at terminal 5
quickly to zero, at which instant the ramp-generator proper takes over. Basically, C210 is the charging
capacitor, and the other components serve either as charging resistors or linear elements. Potentiometer
R227, ramp voltage per second adjustment (RAMP V/SEC ADJUST), serves to determine the rate of
charge of capacitor C210, and consequently, the rate of rise of the voltage applied to the detector plates.
The ramp that is generated by the ramp generator appears at terminal 5, where its maximum is only 6.2
volts. From terminal 5, it is connected to the high voltage generator on the power supply printed circuit
board, where it controls the generation of the high voltage, as explained in the functional description of
the power supply printed circuit board.

Monitoring Circuits of The ECS Board
The input to the monitoring circuits of the ECS board is on terminal 1, the output on terminal 8. The input
on terminal 1 is effectively proportional to the current produced in the detector by the application of the

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Victoreen 875
Operators Manual
high voltage ramp. The overall circuit that monitors the ECS test also includes U2, described with the
power supplies; and the SAFE/FAIL circuit on the relay driver printed circuit board.
Ultimately, by the action of R218, the charge integration adjustment potentiometer (CHARGE INTEG.
ADJ.), charging capacitor C209, and other auxiliary elements, a DC voltage is produced on terminal 10 of
U201, and an output voltage on pin 8 which results in an input to pin 10 of U208 which will be
approximately zero if the system is operative, and approximately + 15 V it a malfunction is present, or on
channel power-up before the first automatic or manually initiated ECS test.
This signal is the input to the latch-and-flop circuit composed of the NOR circuits U202 (pins 1 to 13). The
latch is quiescent until triggered near the end of the ECS test period by the latch-enable input on pin 1 of
U202. This trigger voltage will cause the output (pin 10 of U202) to flop from a pass indication to a fail
indication if a malfunction exists in the detector cable, or signal input circuit.
If the system is operative, a voltage that is low (6.2 V) will appear at terminal 8; if the system has a
malfunction, a voltage that is high (+15 V) will appear at this terminal (+15 V will appear momentarily
immediately after power on). This voltage determines the action of a comparison circuit U4A, and the
output of U4A determines the action of the SAFE/FAIL circuit.
A block diagram of the entire monitoring circuit of the ECS test is shown in Figure 4-1.

Figure 4-1. Block Diagram of ECS Test

4-8

Function Description
Readout Module876A-1

Safe/Reset Sub-circuits
The three sub-circuits described below are all involved in the operation of the green SAFE/RESET lamp
and its associated alarm:
1. A latch for the SAFE/RESET lamp built around four NOR circuits of integrated circuit U202, with
several auxiliary elements.
2. A threshold detector U201 (pins 8, 9, and 10) ascertains by comparison with a standard voltage
whether the current produced by the ECS ramp is sufficiently high.
3. A one-shot multivibrator, U207, pins 9 to 15, which provides an enable signal to allow the latch
circuit to flop from a pass to a fail condition if the signal from the threshold detector is a fail signal.
This enable signal is necessary because the detector current during the ECS test is higher than the
average normal radiation current. The monitoring circuits must therefore be examined just at the
proper time, which is immediately after the cessation of the ECS current.
It will be noted that a trigger signal from the counter U205 is applied to the base of Q207, whose collector
is connected to Q203. . The purpose of this sub-circuit is to short-circuit capacitor C209, so that the
integration of the ECS may proceed from a stable and repeatable starting point. If the system is a
functioning properly, a 2.57 volt level will be present at terminal 1 at the top of the ramp, corresponding to
the 103 R/h meter indication. If voltage at pin 1 is below 2.48 V at this point, ECS circuitry will indicate
channel failure. See Figure 5-1 and drawing 876A-1-3D. This voltage, applied to the integrator circuit
consisting of R218, R224, C209 and the OP AMP circuit U201, pins 12, 13 and 14, produces a linearly
failing voltage of about 2 V/second at pin 14 of U201. This voltage begins just above 0 V. When it reaches
-6.2 volts, a quick switching action takes place in U201, the important result being a sharp change in the
output voltage (pin 8) from +15 to 0 volts. A low (approximately 0 V) input at pin 10 of U208 results
ultimately in a safe report (green light stays on and the alarm relay is energized); whereas a high
(approximately 15 V) input results in a fail report (green light goes out and alarm relay is de-energized).
For any change in the output of the latch circuit (pin 10 of U202) an enable pulse is required. This signal
is output by one-shot multivibrator U207, pin 9, which receives its input from one of the outputs of the
muting multivibrator U207 (pins 1 to 8).

Muting Circuits of ECS Board
During ECS test, it is possible that the normal current generated by the ECS voltage ramp will exceed the
trip-level chosen for the high and/or alert alarm circuits. To avoid an unwanted alarm, the alarm circuits
are muted during the ECS test--that is the alarm circuits are made inactive, so that their lamps and alarm
relays will not respond during the test. Effectively, this is done by generating voltage pulses in the ECS
circuits which last for the duration of the test, and applying them at appropriate points in the alarm circuits
on the relay driver board, so that the alarm circuitry will be momentarily disabled. Computer and recorder
buffers are also muted during the ECS test.
The circuits of the ECS board that generate the muting pulses are, to some degree, involved with the
ramp-generating and monitoring circuits of the ECS board, since all must be in time synchronization.
Generally speaking, however, the most important elements of the muting circuits are contained in
integrated circuit U207 (pins 1 to 8) and integrated circuit U206 (pins 9 to 15). The muting pulse is a
voltage which starts from zero, rises abruptly to +15 V, lasts about six seconds, and falls abruptly to zero.
Initiation takes place on pin 5 of U207, and the output is taken from pin 13 of U208. The signal for muting
the alarms appears on terminal 9 of the ECS board, but a second path leading to pin 12 of U203 serves
the auxiliary purpose of preventing re-initiation of the manually generated trigger produced by pressing
the ECS button on the panel.

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Operators Manual
(Blank page)

Maintenance, Calibration, and Troubleshooting
Maintenance

Section 5

Maintenance, Calibration, and Troubleshooting
5.1 Maintenance
The monitor is designed to operate for long periods in the containment without attention. The following
replacement schedule should keep the monitor in trouble-free operation.
Every five years - Replace the 4200 microfarad electrolytic capacitor, P/N 92-3005-A (C1 01), and the RFI
line filter, P/N 92-9015A (FL101), located on the 876-1-78 mother board of the 876A-1-108 or 876A-100
Readout Module.
Whenever detector cables are removed - Replace the nickel seals, P/N 877-1-60-1, on the detector
connectors as described in the CABLE-877 procedure in Appendix A.

5.2 Calibration
The monitoring systems require calibration before placing them into service. In addition, they should be
recalibrated at regular intervals during routine service. The length of time between calibration intervals
should be determined by operations personnel. For further calibration information, refer to the applicable
calibration procedure provided in Appendix A.
The high-range containment area monitor underwent a complete electronic and isotopic calibration prior
to leaving the Fluke Biomedical plant. The same electronic calibration procedure is supplied in this
manual. Prior to primary isotopic calibration, the detector's hermetically must be verified. Primary isotopic
calibration requires a highly radioactive source (greater than 400 curies) with National Bureau of
Standards (NBS) traceability. As this is beyond the capability of most facilities to perform, the following
method of verifying detector calibration is used:
Detectors shall either be returned to Fluke Biomedical at a five (5) year interval from the date of delivery
or the owner must establish a procedure to determine that the average A/R/h output current does not
deviate from original factory calibration by more than ± 10%.
To encompass Nureg-0737 guidelines, on-site in-situ calibration checks can be performed with the 87810 High-Range Field Calibrator that is capable of producing a 10 R/h indication on the channel under
test.
Electronic alignment of the 876A Readout may be performed using Functional Test Procedure, TP876A1-108 included in Appendix A, and the standard test equipment as listed in Table 5-1. Personnel must be
fully knowledgeable in the operation of the readout prior to attempting to perform the test.

NOTE
Disconnect Detector 877-1 from Readout Module
876A-1 by removing cables from J1 and J2 before
starting electronic calibration.

5-1

Victoreen 875
Operators Manual

Table 5-1.

Recommended Test Equipment

Range
Accuracy, Current Generator

Accuracy Test Electrometer

Maximum Voltage
Frequency

Current Generator - Test Electrometer
1 x 10-12 Amps to 1 x 10-3 Amps
10-12 Amps ± 10%
10-11 Amps ± 3%
10-10 to 10-7 Amps ± 2%
10-7 to 10-3 Amps ± 0.2%
± 0.2% ± 1 digit with integration time long enough to accumulate 3
significant digits of volts indicated on display V/R ± 0.2% ± 1 digit
Adjustable AC Voltage Source
Low range 140 VAC, high-range 280 VAC
60 Hz
4 ½ Digit Digital Multimeter

Fluke 8600A or equivalent
Ranges
Accuracy

Resistance
Lead Connectors

+ 0 to 100 mV up to + 0 to 100 V (20% over-range)
100 mV range: ± (0.05% of input ± 0.02% of range)
all other ranges: ± (0.02% of input ± 0.01% of range)
> 10 megohms
± 0.03%
± 1%
± 0.3%
Trim Pot Adjustment Tool
Carbon Composition Resistor
10 kilohms, ½ W, 5%
Small alligator clips

Output Voltage
Output Current
Load Regulation
Adjustable Current Limit

DC Power Supply
0 to + 25 VDC
0 to 600 mA
0.01% ± 4 mV
Down to 10 mA

Input Impedance
DC Voltage
AC Voltage
DC Current

Multi-function Counter
Fluke 1900A or equivalent
Frequency
Period
Total Counts

5 Hz to 80 MHz (0.1 to 100 Hz Resolution)
5 Hz to 1 MHz, single and multiple period averages
(1 to 100 nsec resolution)
1 to 999,999 counts

Test Procedure TP876A-1-108
Factory test procedure, TP876A-1-108, contains this information necessary to perform electronic
alignment of the 876A-1-108 Readout Module. This procedure is included in Appendix A.

5-2

Maintenance, Calibration, and Troubleshooting
Troubleshooting

5.3 Troubleshooting
The 875 High-Range Containment Monitor is safety-related equipment. The monitor has been assembled
by techniques and with parts selected for the reliability required in a nuclear application. Any repairs made
to the detector or readout (other than replacement of parts listed in Section 5) may void the safety-related
rating. The troubleshooting procedure that follows is a guide to isolating a fault in the system.
Replacement of parts is at the printed circuit board level only. Printed circuit boards must be returned to
Fluke Biomedical for service.
There are two self-contained system tests available in Containment Monitor 875, the Channel Test and
the ECS Test. In both cases, the procedure is to put a known input into the system, and to look for the
desired output.
There is an important difference between the Channel Test and the ECS Test: the former applies an input
to the readout module (that is, to the first electronic circuit in the Containment Monitor); however, it does
not test the detector or the cables connecting the detector to the readout module. In addition, the Channel
Test applies a DC voltage, whereas the ECS Test applies a ramp voltage to the detector plates,
monitoring the resultant current into the readout module.
The digital multimeter mentioned in Table 5-1 of the calibration section is also recommended for
troubleshooting.
If the ECS Test gives a favorable result, the following conditions exist:
1. The detector cannot have any appreciable malfunction.
2. The cables must have continuity.
3. The ECS board and power supply board must be operative.
4. It is highly improbable that any malfunction exists in the fail/safe circuitry.
5. The amplifier, meter and alarm circuitry must be operative.
Essentially, the Channel Test verifies only #5 of the above. However, in doing so, it incidentally verifies all
of the power supplies except the high voltage power supply.
For clarity, troubleshooting is divided into six divisions:
1. Power supplies
2. Input circuit
3. Meter circuit
4. Alarm circuits
5. ECS board
6. Overall fail circuitry

NOTE
Disconnect Detector 877-1 from Readout Module
876A-1 by removing cables from J1 and J2 before
starting troubleshooting of readout module. The
user will probably wish to disconnect the external
alarms as well. It is the responsibility of the user to
see that the alarms are not set off by disconnection.

5-3

Victoreen 875
Operators Manual

5.4 Power Supply Measurements (P/N 876-1-89 Schematic 876-1-3C)
Turn the 876A-1 on by turning the function switch to the ALL position.

CAUTION
Allow all equipment, including the readout module,
to warm up for at least 60 minutes before
attempting any calibration.
Adjust the mechanical zero of the panel meter (use mirror scale to avoid parallax error) so that the needle
is centered on the first hash mark of the black expanded arc to within 0.50 needle width.
Verify the output voltage of the power supplies as follows (See drawings 876-1-78 and 876-1-89).
Mother Board (P/N 876-1-78, Schematic 876-1-3A)
1. Connect the negative lead of the DMM to TP102.
2. Probe TP101 with the positive lead of the DMM. The DMM should read +24 ± 3 VDC.
Power Supply Printed Circuit Board (P/N 876-1-89, Schematic 876-1-3C)
3. Probe TP5 (white) with the positive lead. The DMM should read -21 ± 2 VDC.
4. Probe TP4 with the positive lead. The DMM should read -10.00 ± 0.01 VDC. Adjust R4 as
necessary to correct this reading.
5. Probe TP2 with the positive lead. The DMM should read + 15.0 ± 0.2 VDC. Adjust R5 as required to
achieve correct readings.
6. Probe TP3 with the positive lead. The DMM should read +14.3 ± 0.4 VDC.
PreamplifierIMeter Board (P/N 876A-1-86, Schematic 876A-1-3E)
7. Probe TP401 on preamplifier meter board with the positive lead. The DMM should read +6.200 ±
0.001 VDC. Adjust R413 as necessary to correct this reading.
Rear Panel
8. Probe the back panel high voltage connector, J2. The DMM should read +506 ± 10 VDC.

5.5 Signal Input Circuit
(P/N 876A-1-35, Schematic 876A-1-92 & P/N 876A-1-75A, Schematic 876A-13B)
The signal input circuit is partly on the preamplifier board, and partly on the relay driver board. It consists
of logarithmic amplifier U301 and its associated circuitry (preamplifier meter board) and amplifier U501
(relay driver board). The output of U501 provides the input for the meter circuit on the preamplifier meter
board and the high and alert alarm circuits on the relay driver board. The alarm circuits are covered in the
"Alarm Circuits" paragraph. The signal input circuit can be tested at two test points, using the CHANNEL
TEST push button to provide a convenient input signal. Voltages at these points should be measured with
no signal input.
1. Disconnect the cable connecting the readout module to the detector. Turn the function switch to
TEST.
2. Measure the voltages at TP501 and TP502 under two conditions: 1) with no signal input; 2) with a
signal input obtained by pressing the CHANNEL TEST push button.
The voltages should be:
No Signal

5-4

Channel Test Signal

Maintenance, Calibration, and Troubleshooting
Signal Input Circuit
TP501
TP502

+5 V
-1.5 V

-2.8 V
+6.3 V

These voltages are approximate and actual values may differ somewhat. Any marked departures from
these values is an indication of a malfunction.

5.6 Metering Circuit (P/N 876A-1-3E, Schematic 876A-1-92)
The signal circuit that drives the meter is U401 (Figure 5-2). This is a voltage follower whose output on pin
9 should equal its input on pin 10.
These signals vary from -1.5 V with no signal to +6.3 V with the CHANNEL TEST push button pressed.
All other faults in the metering circuit should be detectable by resistance measurements.

NOTE
The preamplifier metering board contains a
regulated power supply whose voltage is critical. It
should measure 6.2 ± 0.001 V at TP401. It may be
adjusted by R413.

5.7 The Alarm Circuits (P/N 876A-1-75, Schematic 876A-1-3B)
The alert and high alarm circuits differ only in very minor details, so for troubleshooting purposes, it will be
sufficient to discuss them together. As a matter of fact, they are similar for troubleshooting purposes. E.g.
the simplest way to eliminate certain problems is to replace printed circuit board 876A-1-75. Where the
discussion is given in terms of particular pin numbers for definiteness, the alert alarm circuit is to be
understood, but completely analogous procedures apply to the high alarm circuit. At some points, it is
deemed sufficient to describe the voltage state as simply high or low; at other points, particular voltages
have been given. The maximum high value is +15 V, and the minimum low value is -10 V.
In the alert alarm circuit, if a measurement can be made directly on a pin of an OP AMP, a high reading
will usually be close to +15 V, and a low reading close to -10 V. For example, the normal (low input
current) voltage on pin 1 of U502 is -9.9 V (low) and the voltage at the same point is + 13.7 V when high.
However, if the voltage is measured on the other side of the resistor R510, the high is only +1.45 V,
whereas the low is still the same -9.9 V.
If the Channel Test has shown the system to be operative, the following will be the voltage states at
critical points in the signal chain between test point TP502 and relay K501:
The following are measured voltages at critical points in the alert alarm circuit (muting stages are treated
separately). Reset the alarm after every test.
1) TP502

0 to 6 V depending on strength of radiation

Test Point

*Normal

Channel Test

2) Pin 1 U502

-9.8 V

+13.7 V

3) Junction of R510 and CR501 -9.8 V

+1.45 V

4) Pin 14 U503

+14.1 V

+0.2 V

5) Pin 1 U503

+0.08 V

+13.7 V

5-5

Victoreen 875
Operators Manual
*Normal here signifies a small radiation signal so that the voltage at TP502 is close to zero volts.

NOTE
Both of the solenoids of the alert and high alarm
circuits must operate for the CHANNEL TEST lamp
to light.
The lighting of the CHANNEL TEST lamp does not
of itself show that the remote alarm contacts have
closed (See Relay Driver Schematic, drawing
876A-1-3B.)
However,
simple
resistance
measurements and reference to the relay driver
schematic can assure that the output to the remote
alarms is correct.

5.8 High Alarm Circuit
Troubleshooting in the high alarm circuit is completely analogous to that in the alert alarm circuit. Voltages
may be slightly different because R513 may be set differently from R509. However, the high and low state
should be recognizable.

5.9 Muting Stages of the Alarm Circuits
The muting stages of the alarm circuits (U502 pins 8, 9, 10 and pins 12, 13, 14) can cause trouble in two
ways:
1. They can fail to mute the alarm circuits during the ECS Test, thus causing the alarms to sound
when this is undesired.
2. They can mute the alarms when the alarms should sound. This is the more undesirable of the two
possibilities.
If the CHANNEL TEST lamp lights when the CHANNEL TEST push button is pressed, the second
possibility is eliminated. Conversely, if it does not light, malfunction in the muting stages is among the
problems that must be considered in addition to those in the signal chain (also a light burn-out).
Critical voltages in one of the two muting OP AMPS of U502 are:
Normal (Low Signal Level)

Channel Test

ECS TEST

Pin 10
Pin 9

+2 V
0V

+12.88 V*
0V

Pin 8

+13.7 V

13.7 V

+2 V
+12 V*
(Muting voltage)
-9.8 V

* An especially high voltage (12.88 V) is place on pin 10 during the Channel Test to overcome the +12 V
that is placed on pin 9 during the ECS Test. Muting is not desired during the Channel Test. Although
there is only a slight possibility that an automatically initiated ECS Test would take place during a Channel
Test, it is desired to eliminate even this slight possibility.

5-6

Maintenance, Calibration, and Troubleshooting
Muting Stages of the Alarm Circuits

Conversely, during the ECS Test muting is definitely wanted, and the +12 V on pin 9 can easily overcome
the +2 V on pin 10.

5.10 ESC Board (P/N 876A-1-92, Schematic 876A-1-3D)
The wave-shapes shown in Figure 5-1 should be sufficient for localization of malfunction on the ECS
board. Test points A to S are shown on 876A-1-3D. The wave-shapes at the lettered test points are drawn
to the same time scale and also synchronized in time.
The wave-shape at the top of Figure 5-1 is the output at TP201. It is the main synchronizing waveshape
for the lettered wave-shapes, but it is drawn to a different time scale.
These wave-shapes are best used in connection with the discussion of the ECS circuitry.

CAUTION
Electrostatic discharge precautions should be
followed when servicing the ECS board, due to the
MOS FET devices located on it.

5-7

Victoreen 875
Operators Manual

Figure 5-1. Wave Shapes on the Electronic Check Source
Board

5-8

204

205

206

203

207

CONN

206

CONN

0203

208

201

208

202

Maintenance, Calibration, and Troubleshooting
Overall Fail Circuitry Associated with the ECS Test

5.11 Overall Fail Circuitry Associated with the ECS Test
Because the ECS Test involves circuits on the switch printed circuit board, power supply printed circuit
board and relay driver printed circuit board, as well as those on the ECS printed circuit board, a fairly
detailed study of this overall circuitry has been included. The study is devoted not only to circuitry, but in
great part to the interconnections between the printed circuit boards involved.

5.12 Starting With Pins M and P on the Power Supply
Schematic
These pins are ultimately connected to the two inputs of OP AMP U2.
The muting signal input, (15 V), is connected to pin 2 (-). It must pass through a diode to get to pin 2.
There is also a second input to pin 2 from the high voltage 506 V. But the second input is connected to
pin 2 by high resistance, and even if the high voltage falls to 0, the muting signal can overcome it, and
prevent the circuit from going into an alarm condition.
A voltage of either 0 V or 14 V is connected pin 3 (+) of the OP AMP. (There is also connected to pin 3 a
resistor of 130 kilohms whose other end is at 6.2 V.) In the operation of the OP AMP, a 0 V input to pin 3
is a pass condition (green light will stay on) and 14 V is a fail condition (green light will go off), and alarm
relays will be de-energized.
The output of the OP AMP goes from terminal N of the power supply board to the fail/safe circuit on the
relay driver board, via terminal H.

5.13 Starting With Terminal H on Relay Driver Board
If the input on pin H is low (-9.25 V measured), the output on pin 4 of the K503 solenoid is low (0.148 V
measured). When the input on pin H is high, the output is high (14.5 V measured). When pin 8 of U503 is
low, the solenoid has almost 14 V across it and is energized; when pin 8 is high (U503 cut off), the
solenoid has no voltage difference across it. The common point connecting the collector of Q501 and the
base of Q502 has a high (SAFE) of only 0.8 V and a low of 0.03 V, but this change is enough to cause
switching, since conduction in Q502 occurs when its base rises above 0.5 V.
The output of the FAIL/SAFE circuit, on pin F, is connected directly to one terminal of the green lamp on
the switch printed circuit board (effectively also the panel), and the other terminal of the green lamp is
connected directly to +14 V. Consequently, a low input to pin H on the relay driver board puts 14 V on
both terminals of the lamp and goes out.

5.14 Provision of Inputs to Terminals M and P on the Power
Supply Board
Operation of the green lamp is the same for manual and automatic reset functions. The closing of the
ECS switch causes a sharp negative pulse to be generated by the differentiating circuit R217-C205. The
differentiated pulse is passed to the anti-initiate circuit whose purpose is to prevent malfunction in case
the ECS button is inadvertently pressed twice. The circuit consists of two sections of U208 (pins 3, 4, 5, 6,
and 7). It has two outputs:
1. From pin 5 a pulse is sent to U206, another pulse generator that provides a more powerful pulse or
the initiation of the low voltage ramp, 0 to 6.2 V.

5-9

Victoreen 875
Operators Manual

2. An auxiliary pulse from pin 3 of U208 to the automatic pulse generating circuits resets them so that
an automatically generated pulse will be present 17.1 minutes later if the ECS Test is not
conducted manually during that time. The purpose of this pulse is to insure continued operation of
automatic testing.

5.15 Outputs of U206 Pulse Generator on the ECS Board
We have noted that U206 can be triggered by pressing the ECS button. Its main output is a power pulse
to the ramp generator. However, it also initiates a pulse from U203 (pin 10) to pin 5 of U207A, the muting
multivibrator. The muting multivibrator also has two outputs:
1. One output to U203 that ultimately causes a muting pulse six seconds wide at terminal 9. This is
coupled to the power supply board on pin M. It also returns to the circuit so that jitters will be
eliminated on manual ECS.
2. A second output to U207 is a one-shot multivibrator that provides an enabling pulse to the latch
circuit (which also contains a flip-flop). The latch circuit consists of four NOR gate sections of U202
(pins 1 through 6 and 8 through 13), and also inverter U208 (pins 9 and 10). The latch circuit output
is taken from terminal 8, and will be either 6.2 V or 14 V. The operation is explained below.

5.16 Operation of the Latch Circuit
The latch circuit has two inputs and one output:
Input 1 - Enters on pin 6 (U202) and pin 10 (U208), which are connected. This is the monitoring input.
Its value is the result of the ECS Test. It enables the circuit to change state only after the conditions
brought about by the ECS Test have stabilized.
Input 2 - Enters pin 1 (U202) and pin 5 of U202 which are connected. The output is taken from pin 10
and pin 2 of U202, which are connected.
Output - The output may be either 0 V, which is a pass indication, or +14 VDC, which is a fail indication.
The two NOR gates (pins 8, 9, 10, and pins 11, 12, 13) are effectively a flip-flop circuit which will
change its state only when a certain combination of the two inputs is present. The presence of CR201
and a pull-up circuit on the power supply printed circuit board permits pin 10 to be 0 while terminal 8 is
6.2 V.
Input 1 has a normal resting voltage of +15 V. However, during the ECS Test it takes on a voltage
determined by the steady detector current that exists during the ECS Test. This current generates a
voltage of about 2.57 V (0.33 scale) in the panel meter, at which time pin 6 of U202 is at approximately 0
V. If, at this instant, the enabling voltage (input 2) arrives, it will cause the flip-flop to switch states.
Input 2 is initiated by pressing the ECS button, but its actual occurrence in time is delayed so that it
occurs during the flat portion of the current cycle generated by the ECS ramp.
Assume that the green light is ON at the beginning of the ECS Test. Actually this is probable because:
If the green light were off, troubleshooting would not begin with the ECS Test. With this assumption we
can work backwards in the truth table (Table 5-1) from the output (which must be low) to the possible
inputs.
In Figure 5-2, the initial output is assumed low (circuit condition did not show fail prior to ECS Test).
When the enable pulse arrives in the two cases of the signal pulse [pass (L) or fail (H)] the following
conditions exist:
U202, pins 12, 10 L

5-10

(Assumed as initial condition)

Maintenance, Calibration, and Troubleshooting
Operation of Latch Circuit
U202, pins 1, 5, L

(Enable pulse active; i.e. low)

From these conditions, the following must hold true.
Pin

Comment

Depends on 6

Depends on 2

Further analysis is contained in the truth table (Table 5-2).

Figure 5-2. Latch Circuit

Table 5-1. Truth Table for Pass and Fail Conditions in The Latch Circuit

Pin
4
3
13
11
9

Fail Condition
Voltage
State
L (low)
H (high)
H
L
L

(Circuit assumed initially in Pass Condition)
Pass Condition
Voltage Comments

State

Comments

Since 6 is H (high)
Since 1 & 2 are Low
Connected to 3
Since 13 is H
Connected to 11

4
3
8
13
10

H
L
H
L
L

Because 6 is L (also 5)
Because 2 is H
Connected to 4
Connected to 3
Because 8 is H

5-11

Victoreen 875
Operators Manual
8

Connected to 4
Since U202, (8, 9, 10) is
NOR

Result: Output switches
from Low to High

Because 12 and 13 are L
This is the original condition. No
change takes place.

Notes:
1) Enable pulse assumed present, so 1 and 5 are L.
2) Initial condition assumes 12 and 10 L.
The truth table shows that no change in the output can occur without the presence of the enable pulse,
even though the monitoring signal indicates a fail condition. This is necessary because the ramp voltage
starts from zero during the ECS Test.

Table 5-2.

Signal In Fail State (High Signal Input)

Pin 1
10, U208 and 6, U202
9, U208 and 2, U202
1,5, U202
4, 8, U202
3, 13, U202
10, 12, U202

Voltage State
H
L
H
L
L
L

Comments
Fail state
After inversion
No enable input
Because of NOR action
Because of NOR action
Because of NOR action

Thus the circuit does not react to a fail signal input unless pins 1 and 5 are low.

NOTE
If a problem cannot be resolved by applying the
troubleshooting and maintenance procedures
provided here, please contact Fluke Biomedical at
440.248.9300 for assistance.

5-12

Appendix
Calibration and Test Procedures

Appendix A

Calibration and Test Procedures
A.1 Calibration Procedures
Document Number

Description

CAL877-1

High Range Detector 877-1 Calibration

REPORT 877

Calibration of Model 877 to 3.0 MeV

The calibration and data listed above is for reference only and need not be performed.

A.2 Test Procedures
Document Number

Description

TP876A-1-108
Monitor

Test Procedure 876A-1-1 08, High Range Containment Area

TP877-1-5

Test Procedure for 877-1-5, HRCM Detector

A-1

Victoreen 875
Operators Manual
(Blank Page)

Appendix
Cable and Pull Box Procedures

Appendix B

Cable and Pull Box Procedures
B.1 Cable and Pull Box Procedures
Document Number

Description

CABLE-877

HRCM Cable Termination and Installation Procedure

878-12-3
Procedure

High-Range Containment Monitor Pull Box Cover Installation

B-1

Victoreen 875
Operators Manual
(Blank page)

Appendix
Applicable Drawings and Bill of Materials

Appendix C

Applicable Drawings and Bill of Materials
C.1 Applicable Drawings
Document Number

Description

GEL876-1-55

Rack Chassis & Recommended Seismic Mtg.

GEL876A-1

Readout Module Dimensional Outline

GEL875-1

Interconnection Diagram High-Range Containment Monitor

GEL-877-1

High-Range Detector & Bracket Dimensional Outline

876-1-114

Support Strap

844-8-5

Blank Panel Assembly

876-1-55

Rack Chassis

876A-1-108

High Range Containment Monitor Readout Assembly

876A-1-86

Preamp/Meter PC Board Assembly

876-1-100

Preamp Shield Assembly

876A-1-3E

Schematic Preamp Meter PC Board

876A-1-92

High-Range CAM ECS PC Board Assembly

876A-1-3D

Schematic ECS PC Board

876-1-89

Power Supply PC Board Assembly

876-1-3C

Schematic Power Supply PC Board Assembly

876-1-89A

Voltage Regulator PC Board Assembly

876-1-93A

Schematic, Regulator PC Board Assembly

876A-1-75A

Relay Driver PC Board Assembly

876A-1-3B

Schematic Relay Driver PC Board

876-1-104

Switch PC Board Assembly

876-1-3J

Schematic PC Switch Board

876-1- 78

Mother PC Board Assembly

876-1-3A

Schematic Mother PC Board

Document Number

Description

876-1-107

Rear Panel Assembly

876-1-85

Rear Panel Assembly

C-1

Victoreen 875
Operators Manual
876-1-3G

Schematic, PC Board

876A-1-40

Front Panel Assembly

876A-1-41

Meter Assembly

876A-1-3H

Schematic (Block Diagram.) Final Assembly

92-9015-A

AC Line Filter

877-1-5

Detector Assembly

877-1-81

Containment Area Detector Assembly

877 -1-80

Detector Mounting Flange Assembly

877-1-17

Wall Mounting Bracket

878-1-5

Detector Cable Assembly

878-1-15

Cable Termination Kit

878-1-9-TAB

Detector Cable - In Containment

50-103-TAB

Detector Cable - Out of Containment

878-12-5

Cable Pull Box Assembly

878-12-30 (TAB)

Flexible Metal Hose Assembly

C-2

Appendix
Applicable Bill of Materials

C.2 Applicable Bill of Materials
Document Number

Description

875-1

876A-1 Readout with 877-1 Detector

876A-1

High-Range Containment Monitor Readout

876-1-55

Rack Chassis

876A-1-108

High-Range Containment Monitor Readout Assembly

876A-1-Kit

Mating Connector Kit for 876A-1-108

876A-1-86

Preamp Meter PC Board Assembly

876-1-100

Preamp Shield Assembly

876A-1-92

High-Range CAM ECS PC Board Assembly

876-1-89

Power Supply PC Board Assembly

876-1-89A

Voltage Regulator PC Board Assembly

876A-1-75A

Relay Driver PC Board Assembly

876-1-104

Switch PC Board Assembly

876-1-78

Mother PC Board Assembly

876-1-107

Rear Panel Assembly

876-1-85

Rear Panel Assembly

877-1

High Range Detector

877-1-5

Detector Assembly

877-1-81

Containment Area Detector Assembly

877-1-80

Detector Mounting Flange Assembly

878-1-5

Detector Cable Assembly

878-1-15

Cable Termination Kit

878-12-5

Cable Pull Box Assembly

844-8-5

Blank Panel Assembly

C-3

Fluke Biomedical
Radiation Management Services
6045 Cochran Road
Cleveland, Ohio 44139
440.498.2564
120 Andrews Road
Hicksville, New York 11801
516.870.0100
www.flukebiomedical.com/rms

C-4

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