Acom A1010 ACOM 1010 User Manual Exhibit6 1010
Acom International Inc ACOM 1010 Exhibit6 1010
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users manual
Exhibit 6 page 1 of 15
International, Inc.
Exhibit 6: User’s Manual
External Radio Frequency
Power Amplifier ACOM 1010
Model 1010
71 West street
Medfield, MA 02052
Tel: 508 359 5990
fax: 508 359 5989
E-mail: aa1nd@aol.com
Exhibit 6 page 2 of 15
TABLE OF CONTENTS
1. GENERAL INFORMATION .......................................................................................................................................3
1-1. Introduction and Description......................................................................................................................................3
1-2. Owner Assistance .........................................................................................................................................................3
1-3. Equipment Supplied.....................................................................................................................................................3
1-4. Features .........................................................................................................................................................................3
1-5. Safety Considerations, Explicit Definitions...............................................................................................................4
2. INSTALLATION.............................................................................................................................................................5
2-1. Unpacking and Initial Inspection ...............................................................................................................................5
2-2. Line Voltage Selection..................................................................................................................................................5
2-3. Amplifier Location Selection.......................................................................................................................................5
2-4. Connections...................................................................................................................................................................5
3. POWER ON, CONTROLS AND INDICATORS........................................................................................................7
4. OPERATION ...................................................................................................................................................................9
4-1. Turning ON and OFF ..................................................................................................................................................9
4-2. Changing Operate and Standby Modes.....................................................................................................................9
4-3. RTTY Mode ................................................................................................................................................................10
4-4. Antenna change ..........................................................................................................................................................10
4-5. Tuning..........................................................................................................................................................................10
4-6 The Auto-Protection System ......................................................................................................................................12
5. MAINTENANCE...........................................................................................................................................................12
5-1. Cleaning.......................................................................................................................................................................12
5-2. Fuse Replacement.......................................................................................................................................................13
5-3. Tube Replacement......................................................................................................................................................13
5-4. Simplified Schematic Diagram .................................................................................................................................13
6. SPECIFICATIONS .......................................................................................................................................................15
6-1. Parameters ..................................................................................................................................................................15
6-2. Functions .....................................................................................................................................................................15
6-3. Storage and Shipment................................................................................................................................................15
Exhibit 6 page 3 of 15
1. GENERAL INFORMATION
Congratulations on purchasing one of the finest HF amplifiers in the world today. Acom is pleased that you
have chosen one of our products, and we will endeavor to provide you with the information and support you
need to enjoy your purchase for many years. We urge you to read all of the following materials before you
embark on operating your new amplifier.
1-1. Introduction and Description
This manual explains the installation, operation, and maintenance of the ACOM1010 HF linear amplifier.
The ACOM1010 is a self-contained linear amplifier that covers all amateur bands, from 1.8 through 29.7
MHz. It provides over 700-W PEP of output power (or 500 W in continuous-duty operation) with less than
60-W of drive. The amplifier is designed to tolerate VSWR levels of up to 3:1 throughout its operating
range, and tuning is simplified by Acom’s exclusive True Resistance Indicator (TRI). Also, a built-in antenna
selector switch with two outputs is included to provide instant choice of antennas. Importantly, a variety of
system parameters are continuously monitored and available to the operator to assure safe and efficient
amplifier operation.
1-2. Owner Assistance
If technical or operating assistance is needed, your local dealer should be contacted first. In the unlikely
event you need further information, you may get in touch with Acom by facsimile, telephone, email or
standard mail. Fax: + 359 2 920 9656; telephone: + 359 2 920 9655; e-mail: acom@mail.orbitel.bg;
standard mail: Acom bul. N.Mushanov Nr.151, 1330 Sofia, Bulgaria.
1-3. Equipment Supplied
The ACOM1010 amplifier and this manual are shipped in a cardboard carton.
1-4. Features
• Easy operation. The plate-load True Resistance Indicator (TRI) is an ACOM innovation that provides
quick and precise tuning, typically in less than 10 seconds. The auto-operate function will return the
amplifier to the OPERATE mode automatically after each protection trip, saving time and avoiding manual
switching.
• No tuner needed. No external antenna tuner is required as long as the antenna VSWR is 3:1 or lower.
The amplifier will perform the functions of an antenna tuner, enabling you to change antennas faster and
use them over wide frequency ranges.
• A durable amplifier. This amplifier is both user-friendly and self-monitoring. It is designed to safely
withstand up to 240 W of reflected power, up to 100 milliseconds of drive spikes (RF "tails" after a PTT or
KEY release), and even operator tuning errors. It is also capable of operating at more than half its designed
output power at only 75% of nominal line (mains) voltage. Because it can tolerate deep voltage drops
(down to zero for 10 milliseconds) and 15% line voltage spikes, it is particularly suited for use in portable
environments, such as field days and DXpeditions.
• LED bar-graph display. The upper LED bar-graph always reads peak forward power while the lower
LED bar-graph is for the reflected power. LED warning indicators are provided for abnormal conditions of
grid 1, grid 2, and plate parameters.
• Antenna selection. Two antenna outputs are selectable on the front panel of the amplifier.
• Efficient tuning. Antenna matching can be achieved in less than 10 seconds and at a quarter of nominal
output power, which produces lower risk of interference to other stations and greater safety to the amplifier
components.
• Transceiver-independent. The amplifier operates without special signaling from the transceiver; it
needs only "ground on TX" and 60 W RF drive power to operate at full output power.
• Input matching. Broadband input matching circuitry offers excellent loading characteristics for the
driving transceiver, from 1.8MHz to 30MHz.
• Single tube operation. A single Svetlana 4CX800A (GU74B) high-performance ceramic-metal tetrode
with plate dissipation of 800W (forced air cooling, grid-driven) is used for maximum efficiency.
• Permanent monitoring and protection of the plate and grids currents. The Bias Optimizer minimizes heat
dissipated by the tube, assuring tube longevity.
Exhibit 6 page 4 of 15
• High voltage protection. Design of the high-voltage power supply eliminates the danger of turn-on
transients affecting sensitive devices connected to the same line (mains) circuit. Moreover, the amplifier can
be configured to accommodate any of 8 nominal line voltages between 100 and 240 V, 50 or 60 Hz.
• Band inclusion. The amplifier can be shipped with 10 and 12-meter capability disabled as required by
the Federal Communications Commission (FCC), for United States users. Contact your dealer about
enabling those bands.
1-5. Safety Considerations, Explicit Definitions
The ACOM1010 HF Linear Amplifier is a Safety Class I unit. The grounding lead (yellow with 2 green
stripes) of the power cable and the ground stud on the rear panel of the amplifier (marked GND) must be
connected to the station's grounding system for safe operation. The amplifier is designed to meet
international safety standards and complies with CE safety and electromagnetic compatibility requirements,
as well as FCC regulations. This operating manual contains an assortment of precautions and warnings
that MUST BE FOLLOWED BY THE USER to ensure safe operation of the amplifier.
The safety definitions below apply to this operating manual:
A warning is associated with a procedure that, if not properly performed, could result in a fire hazard or
electric shock, with resulting injury or death to the user.
A caution is associated with a procedure that, if not properly performed, could result in damage to the
amplifier or other equipment.
A note is associated with a procedure that, if not properly performed, could result in inconvenience or
physical injury to the user.
WARNING HIGH VOLTAGE!
The amplifier works with voltages up to 3000 V dc, which are potentially LETHAL! You must unplug the
amplifier from the line (mains) wall outlet and WAIT AT LEAST 30 minutes before removing the cover of the
amplifier. Do not touch any part inside while the amplifier is open because dangerous voltages may remain
present.
WARNING HIGH VOLTAGE!
NEVER ALLOW ANYONE, ESPECIALLY CHILDREN, to push anything into the case holes or to otherwise
touch the amplifier or its connecting cables. There is grave danger of fatal electrical shock. NEVER
TOUCH AN ANTENNA during transmission as this may result in an electric shock or burns. NEVER
EXPOSE the amplifier to rain, snow or any liquids. AVOID placing the amplifier in excessively dusty
environments. DO NOT OBSTRUCT AIR INTAKE (bottom) or EXHAUST (top cover) areas of the amplifier.
Keep a minimum distance of 50cm (20 inches) clear of the air exhaust opening.
WARNING
Do not undertake or perform any repair or adjustment of your amplifier yourself, including any attempt to
change hardware or firmware. Doing so creates a potentially fatal shock hazard and may damage the
amplifier or equipment connected to it. Acom is not responsible for any such personal injury or equipment
damage, whether caused by accident or as a result of good faith efforts at repair or adjustment.
CAUTION
To avoid damage to the amplifier not covered by Acom’s warranty, the user is expected to read and comply
with the installation instructions contained in Section 2 of this operating manual. If there are any doubts or
questions concerning installation, operation or safety of the amplifier, the user should contact Acom.
Exhibit 6 page 5 of 15
2. INSTALLATION
2-1. Unpacking and Initial Inspection
NOTE
The first step to installation is to fully read this manual. Then, carefully inspect the shipping cartons for any
physical damage. Acom ships amplifiers in highly protected containers, but it cannot assure that
mistreatment by shippers will not occur. If there is any such damage, notify your Acom dealer immediately.
Failure to do so may invalidate your warranty. In any case, be sure to keep all packing materials for possible
future amplifier shipment.
2-2. Line Voltage Selection
CAUTION
To avoid damage to your amplifier and to maintain your warranty coverage, be certain that the amplifier line
(mains) voltage setting corresponds to your nominal line (mains) voltage.
Normally, the amplifier is delivered with the Voltage Selector set for a nominal line voltage of 240 V. If your
line voltage is not 240 V, you must contact your dealer for instructions on how to change the voltage
selector inside the amplifier. The only exception to this is if the unit has been custom ordered, in which case
the voltage selection will be noted in the Table of Individual Data (Table 2-1, below).
AMP s/n
Tube s/n
Voltage Selector VAC
Table 2-1. ACOM 1010 Individual Data
2-3. Amplifier Location Selection
Locate the amplifier as close as possible to where it can be used conveniently. Access to the command
knobs and indicator's area, as well as to the rear panel cabling, will be necessary.
No device that is sensitive to magnetic fields, including dynamic microphones, should be located adjacent to
the right side of the amplifier, where the power transformer is mounted. The amplifier should generally be
placed to the right of your transceiver. No temperature-sensitive devices should be located above the air
exhaust ports. This means the amplifier should not be located under a shelf or other structure that could
impede the free movement of air away from the amplifier.
DO NOT OBSTRUCT AIR INTAKE (bottom) and EXHAUST (top cover) areas of the amplifier. Keep a
minimum clear distance of 50cm (20 inches) above the exhaust opening.
2-4. Connections
Before applying line (mains) voltage to your amplifier, follow the steps listed below in the order they are
presented.
WARNING
Note that your grounding system may have to handle a current of more than 15 Amperes. This requires an
adequately sized and well-maintained conductor of at least 4 mm2 (AWG 11 or SWG 13). If this is not the
case at your operating location, you should make the necessary changes using a licensed electrician.
Exhibit 6 page 6 of 15
(d) (a) (b) ---- (c) ----
Fig. 2-1 Connections
a) Connect the station's grounding system to the wing-nut ground stud of the amplifier (on the rear panel,
marked GND in Fig. 2-1).
b) Connect a suitable coaxial cable between the transceiver output to the amplifier (rear panel) RF INPUT
SO-239 connector, using PL-259 connector.
CAUTION
The coaxial cable from the amplifier's output must be capable of handling the amplifier’s output power
safely, particularly on the 10-meter band. It is suggested that, at a minimum, RG8X (including RG8MINI,
RK50-4-11, RK50-4-13) or, even better, RG213 (including RK50-7-11) coaxial cable be used.
c) Connect a suitable coaxial cable from the antenna to the appropriate amplifier output (on the rear panel,
marked ANT1 or ANT2), using a PL-259 plug.
d) Run a shielded cable from the "ground on transmit" socket or terminal on your transceiver to the
amplifier rear panel KEY-IN socket. The KEY-IN socket uses a standard RCA phono plug.
NOTES
Your amplifier will not work if KEY-IN is not connected properly.
Transceiver producers assign different names to their “ground on transmit” output terminals, e.g., TX-GND,
SEND, T/R-LINE, etc. Some transceivers may require that "ground on transmit" be implemented by a
software command, or by changing the setting of a switch on the rear panel or inside the transceiver. Check
your transceiver's manual for more information on keying amplifiers.
e) Preparation of the wall outlet for the amplifier.
WARNING
If your amplifier is only fitted with one line (mains) fuse, it is suitable for the European Community ONLY.
Your dealer will check that your amplifier is correctly fused before it is shipped to you, based upon your
indicated location. Customers should check with a qualified electrician if the amplifier is to be used outside
the country in which it was purchased.
Due to different line (mains) standards in different countries, the dealer will provide the correct Safety Class
I plug for your location. The ground lead of the power cable is colored yellow with two green stripes. If you
have any doubts about the correct way to connect these wires, consult your dealer.
Exhibit 6 page 7 of 15
WARNING
Before connecting the amplifier to your line (mains) supply, be sure that the line (mains) supply is correctly
wired and is capable of providing the required current, i.e., up to 5 A from 240 V and 10 A from 120 V. As
discussed earlier, it is very important that the ground lead is adequately sized and properly connected.
The Power Switch on the front panel must be in the OFF position; only then should you insert the amplifier's
line (mains) plug into the appropriate wall outlet. At this time the amplifier remains switched off.
3. POWER ON, CONTROLS AND INDICATORS
CAUTION
Do not turn the amplifier on for at least 2 hours after unpacking it and locating in its operating location. Pay
particular attention whenever the amplifier is moved from a very cold place to a very warm one because
unseen condensation may develop, and this could result in damage to the high voltage circuits of the
amplifier. Under these circumstances, do not turn the amplifier on for at least 4 hours. A similar effect could
occur following rapid warming of the location, such as winter use of a powerful electric heater.
CAUTION
To avoid damage that may not be covered by the amplifier warranty, carefully check that the voltage for
which the amplifier is set corresponds to your nominal line (mains) voltage. See Section 2-2 and Table 2-1.
After following all instructions in Section 2, you may now turn ON the main POWER switch on the front
panel (Fig. 3-1). The green LED indicator above the switch will illuminate:
Fig. 3-1 ACOM1010 Display and Control
Exhibit 6 page 8 of 15
Fig. 3-2 ACOM1010 Display Window
Note that the upper LED bar-graph always reads peak forward power, even during STBY. The 800 W-scale
resolution is 50 W. Note also that levels below 50 W may be not detected.
The lower LED bar-graph will indicate reflected power up to 240 W. The scale resolution is 30 W.
The OPER button alternatively switches between the operate and standby modes once the amplifier has
completed its 150-second warm-up period. See Section 4-2.
The RTTY button reduces the output power of the amplifier to 500 W. See Section 4-3. The button labeled
A1-A2 (Section 4-4) changes the antenna output to either antenna 1 or antenna 2, according to the
operator’s choice. It is the operator’s responsibility to connect suitable antennas to the ANT1 and ANT2
connectors on the rear panel of the amplifier.
The red TX LED illuminates whenever the KEY-IN input is keyed (closed to ground), i.e., when the
transceiver goes into the transmit mode. See Section 2-4(d).
The BAND knob controls the band switch, and LOAD and TUNE are used to adjust their respective variable
air capacitors in the amplifier’s output circuit. The settings of these three controls must be changed at each
band change as well as when an antenna is changed. The three LED indicators located above the knob
LOAD are called the “TRI tuning indicator” and they are used to achieve antenna impedance matching
during the a re-tune procedure. Please see Section 4-5 for a discussion of the tuning procedure.
Exhibit 6 page 9 of 15
CAUTION
To avoid damage not covered by the amplifier’s warranty, do not turn the BAND switch while transmitting.
Switching while transmitting is called “hot switching” and it will cause irreparable damage to the band switch.
There are three warning LED indicators and one fault LED indicator located in the bar-graphs window. The
following describe the error conditions and the correct responses:
- G1 – when illuminated, a control-grid overload condition exists; reduce the drive power for safe
operation;
- G2 - when illuminated, a screen-grid overload conditions exists; reduce the drive power and/or refresh
the tuning (Section 4-5) for safe operation;
- IP - when illuminated, a plate current overload condition exists; reduce the drive power and/or refresh
the tuning (Section 4-5) for safe operation;
- F – when illuminated, the amplifier automatic protection has tripped. If F is accompanied with one of the
G1, G2, or IP condition indicators, the cause of the protection trip will be evident. When F alone is
illuminated, check the keying wiring, Section 2-4(d). See Section 4-6 for details about the auto-
protection system.
4. OPERATION
Operation of the amplifier is simplified through Acom’s innovative TRI tuning aid, Auto-Operate function, and
automatic protection systems. To make full use of the amplifier’s potential and to configure it to local
conditions, the following information should be read carefully.
4-1. Turning ON and OFF
In order to turn on the amplifier, press the POWER switch at the bottom-right corner of the front panel. The
LED indicator above the switch will glow green and the audible cooling fan will start. Following a series of
automatic self-tests, the OPER LED will begin to flash green and will continue to do so during the 150-
second warm-up period. Throughout this period, the amplifier will remain in the standby mode, and the
transceiver may continue to be used. Also during this period, the A1-A2 button may be pressed to change
antennas, i.e., between the antennas connected to the ANT1 and ANT2 terminals on the rear panel of the
amplifier. Switching between the antennas does not affect the warm-up process.
CAUTION
To avoid damage not covered under warranty, do not change the antenna output during a transmission, i.e.,
never press the A1-A2 button when transmitting.
NOTE
When you intend to have a short operating break, it is better to place the amplifier in the standby mode
rather than turning it off. Tube life is shortened by repeatedly turning it on and off.
After the warm-up period is complete, the OPER LED stops flashing and remains illuminated green.
4-2. Changing Operate and Standby Modes
The OPER button changes between two modes. When the green light above the button is illuminated, the
amplifier will remain ready to operate, even automatically returning from standby after a high-drive
protection trip. That is, after a protection trip, e.g., from an overdrive event, the amplifier will normally shift to
the STBY mode for several seconds, but it will automatically return to the OPER mode after that. This is the
Auto-Operate feature. Alternatively, the OPER button may be depressed manually to go to and remain in
the STBY mode, such as when you leave the station temporarily. The green LED goes off and the Auto-
Operate function is suppressed temporarily. Pressing the OPER button again restores the Auto-Operate
feature.
Exhibit 6 page 10 of 15
4-3. RTTY Mode
Select the RTTY mode to operate continuous-duty modes such as RTTY, SSTV, or other data modes. The
LED indicator above the RTTY button illuminates and the amplifier operating parameters are changed to
reduce tube dissipation. In the RTTY mode, the amplifier output power is reduced to a maximum of 500 W.
There is no need to adjust tuning when changing between RTTY and normal modes.
CAUTION
To avoid damage not covered under warranty, do not change modes during transmission. That is, do not
change to or from RTTY or any other mode when transmitting.
4-4. Antenna change
By pressing the A1-A2 button, the amplifier output is switched between the two corresponding antenna
outputs, ANT1 and ANT2. The lights above the button indicate the current antenna selection.
CAUTION
To avoid damage (not covered under warranty) do not change the antenna during transmission.
4-5. Tuning
Tuning is possible only in the OPER mode.
a) Preliminary information.
Tuning the amplifier involves a procedure of matching the impedance of the antenna and transmission line
to the amplifier tube’s characteristic load resistance. This will ensure maximum plate efficiency and RF gain
at nominal output power, with minimal distortion and spurious output. Note that REFLECTED POWER
readings depend on the antenna and transmission line impedances only, and not on amplifier tuning. If the
load impedance is not a nominally resistive 50-Ohms, the REFLECTED POWER reading will always show a
reading, no matter what the tuning settings. Proper tuning is always necessary, however, and will allow you
to operate at a high power level, without distortion or any danger to the amplifier. Note also that the real
OUTPUT POWER presented to the load (the antenna and transmission line) is equal to the difference
between the FORWARD and REFLECTED power readings. For instance, with a 2.5:1 VSWR, readings of
800 W and 150 W FORWARD POWER and REFLECTED POWER, respectively, the real OUTPUT
POWER is 650 W. At very high VSWR levels, such as when no antenna is connected or a badly
mismatched antenna is used, the FORWARD and REFLECTED readings will be almost equal, while the
real OUTPUT POWER (the difference between them) will be nearly zero. The amplifier can operate safely
as long as the REFLECTED POWER is LESS THAN 250 W. Matching is assured for loads presenting a
VSWR of up to 3:1. Nevertheless, for some loads and bands, matching is possible at even higher VSWR
levels, but the drive power must be reduced to prevent the REFLECTED POWER from exceeding 250W.
Failure to comply with these guidelines will cause the protection circuits to trip. For example, if the antenna
VSWR were 5:1, the maximum attainable forward power would be 540 W, 240 W of reflected power and
real output to the antenna and transmission line of only 300 W. In the event your antenna cannot be
adjusted to produce a lower VSWR, an external antenna tuner may be deployed.
CAUTION
At elevated VSWR levels, high voltages and high currents are distributed along the coaxial cable to the
antenna, risking internal arcing and heat generation, and likely damage to the cable and any antenna
switches that may be used. It is recommended that VSWR levels of more than 3:1 not be permitted with
coaxial cable above 14 MHz.
It is advisable to adjust amplifier tuning when antennas have been changed, snow has fallen, new objects
are in the near field of the antenna, etc. Such changes may affect antenna impedance.
NOTE
If you use more than one antenna on a band, the proper antenna must be selected prior to performing the
tuning procedure outlined below.
Exhibit 6 page 11 of 15
CAUTION
To avoid damage not covered under warranty, do not switch the BAND switch knob while transmitting. As
discussed above, hot switching will damage the amplifier’s band switch!
CAUTION
Also, never apply drive longer than one minute continuously without pausing for at least one minute to allow
the tube to cool.
It is recommended that for initial tuning a frequency in the middle of the band be used. First, with no
transceiver power applied, select the band. Then use Table 4-1 to achieve an approximate preset for both
TUNE and LOAD capacitor knob settings:
Band LOAD TUNE
MHz Knob Dial Knob Dial
1.800 - 2.000 42 - 71 55 - 28
3.500 - 4.000 32 - 57 52 - 31
7.000 - 7.300 29 - 40 36 - 27
10.100 - 10.150 59 - 66 50 - 44
14.000 - 14.350 33 - 39 42 - 30
18.068 - 18.168 17 - 35 60 - 50
21.000 - 21.450 50 - 60 15 - 10
24.890 - 24.990 38 - 42 80 - 72
28.000 - 29.700 51 - 64 41 - 24
Table 4-1. Approximate tuning preset
b) Tuning Procedure.
(1) Once the antenna and band have been selected (and the TUNE and LOAD adjustments have been
initially set as indicated in Table 4-1), apply between 10 and 20 W of continuous (key down CW) signal.
(2) Look at the upper LED bar-graph (FORWARD POWER) and adjust the TUNE (right hand) capacitor for
maximum indication.
(3) Watch the TRI indicator above the LOAD (left hand) capacitor and turn the LOAD capacitor in the
indicated direction to center the green LED indicator light.
(4) Increase the drive power to get the desired nominal output; then repeat steps (2) and (3), always
peaking output with the TUNE adjustment.
NOTE
No light on the TRI indicator means that the tuning is too far off. To correct this, turn the LOAD and TUNE
knobs around the table-suggested positions until the TRI indicator illuminates.
no light: tuning is far left: tuning is far right: marker inside: LOAD is tuned:
use TUNE knob turn LOAD knob turn LOAD knob turn LOAD knob turn TUNE knob
for max. Power to the right to get to the left to get slightly left to peak Forward
to get any marker the inside markers inside markers to center it Power
Fig. 4-1. Using TRI tuning aid
The TRI indicator will not illuminate until at least 20 W of forward power (output) is achieved. In the event
successful matching cannot be accomplished, check the BAND switch position and antenna selection. Then
check the antenna VSWR at the same drive frequency.
Exhibit 6 page 12 of 15
d) Tuning hint. A benefit of TRI is that the knob positions are virtually independent. The plate-load
resistance decreases to the right and increases to the left of the TRI center. A centered tuning indication
corresponds to the proper LOAD capacitor tuning, which presents an optimum load resistance to the tube.
If the LOAD knob is turned to the left with a centered TRI, there will be more gain, but less linearity. When
available drive power is insufficient or when less output but better efficiency are needed, e.g., for RTTY and
SSTV, this may be desirable. Tuning to the right of the center would lead to the opposite result, i.e., less
gain and more power attainable. Of course, this requires more drive power, more plate current, and more
plate heat, which shortens tube's-expected life. Off -center tuning may also be used to compensate for line
(mains) voltage variations in order to maintain tube efficiency. In that case, tune to the left when line
(mains) voltage is high, or tune to the right if it is low. However, where there is more than a 10% difference
from the nominal line (mains) voltage, the voltage selector inside the amplifier should be changed. See
Section 2-2 (Line Voltage Selection).
4-6 The Auto-Protection System
When any abnormal amplifier condition is detected by the auto-protection microprocessor, the risk will be
evaluated automatically and either of two levels of protection will be applied:
.
a) The first degree of protection consists of an illuminated LED warning. These include the yellow LED
warnings discussed earlier, i.e., "G1” (grid 1), "G2," (grid 2), and “IP” (plate). Operation may be
continued but the amplifier is likely to proceed to the second degree of protection, the trip.
b) The second degree of protection is a trip to the standby mode. The red “F” (fault) LED illuminates and
the amplifier automatically goes to the standby mode for several seconds. Also, the green OPER LED
goes off. The amplifier will indicate the reason for the protection trip:
- if one of the yellow (G1, G2, IP) warning LEDs is illuminated along with the “F” LED, a current limit has
been exceeded; drive power must be reduced or retuning is necessary;
- if the last red LED of the reflected-power bar-graph is illuminated together with the “F” LED, the
reflected-power limit has been exceeded; the drive must be reduced or the antenna VSWR must be
improved.
- if all three LEDs of the TRI are flashing simultaneously together with the “F” LED, the tuning is not
adjusted correctly; most likely the antenna impedance has changed and retuning is required.
Fault information normally remains on the display for several seconds while the amplifier is in the standby
mode. The auto-operate function will attempt to return the amplifier to the operate mode automatically. If
the protection trips repeatedly, the user must attend to the cause of the trip, which is typically too much drive
or antenna mismatch.
CAUTION
If all LEDs in the bar-graph window are flashing simultaneously, you must immediately switch off the
amplifier to avoid damage.
5. MAINTENANCE
If no indicator glows upon switching the amplifier on, the main fuse(s) may have blown. See Section 5-2.
5-1. Cleaning
WARNING
Do not use solvents for cleaning as they may be dangerous to you and damage amplifier surfaces and
plastic components.
Do not open the amplifier. Cleaning the amplifier outer surface may be safely accomplished by using a
piece of soft cotton cloth lightly moistened with clean water.
Exhibit 6 page 13 of 15
5-2. Fuse Replacement
CAUTION
For 120 V ac operation, the fuses should be rated at 10 A; for 240 V ac operation, the fuses should be rated
at 6.3 A. If it is necessary to replace the line (mains) fuses, use only those that are permitted under local
safety codes.
The two primary line (mains) fuses in the amplifier are located on the rear panel (Fig. 2-1). They are of the
fast (quick blow) type, European size 5 x 20 mm. Use 10 A for 100-120 V ac operation; 6.3 A for 200-240 V
ac operation. Suitable types are:
For 120 V: 10 A 250 V 5 x 20 mm fast (quick blow), Littlefuse 0217010; Wickmann 1942100000
For 240 V: 6.3 A 250 V 5 x 20 mm fast (quick blow), Littlefuse 021706.3; Wickmann 1931630000
Besides the primary fuses, there are also fuses located on the HV PCB and on the MAINS PCB (inside the
amplifier). They are European size 5 x 20 mm, 2 A and 5 A, time lag (slow-blow) type.
Suitable types are:
HV PCB: 2 A 250 V SLOW BLOW (Time Lag) 5 x 20 mm; Littlefuse 0218002; Wickmann 1951200000
MAINS PCB: 5 A 250 V SLOW BLOW (Time Lag) 5 x 20 mm; Littlefuse 0218005; Wickmann 951500000
These latter fuses must not be replaced by the user. Replacing these internal fuses is potentially dangerous
and must be done only by a trained service technician. Contact your Acom dealer for assistance.
5-3. Tube Replacement
A single Svetlana 4CX800A (GU74B) high-performance ceramic-metal tetrode is used in the amplifier.
Replacement is a complex and potentially dangerous operation that involves adjustment of the plate idling
current. This should not be attempted by the user. Contact your Acom dealer.
5-4. Simplified Schematic Diagram
See Fig. 5-1 ACOM1010 Simplified* Schematic Diagram. The 4CX800A (GU74B) Svetlana high
performance ceramic-metal tetrode (V1) with plate dissipation of 800 W is grid-driven. The input signal from
the RF INPUT jack is passed through a broadband input matching circuit, which consists of components on
the INPUT PCB and includes the drive-power swamping resistor Rsw. This circuit tunes out the input
capacitance of the tube. The swamping resistor Rsw is a termination load for the matching circuit and can
dissipate up to 80 W of RF drive power. It also eliminates any tendency toward oscillation by the tube,
ensuring excellent RF stability of the amplifier.
The cathode resistor Rc creates DC and RF negative feedback, thus stabilizing gain and equalizing
frequency response. The combination Lp1-Rp1 in the plate circuit is a VHF/UHF parasitic suppressor. DC
plate voltage is fed through chokes RFC1-RFC2 and the capacitor Cb3 blocks it from the output. The output
tank, comprised of LP1, LP2, LL, CP1, CP2, and CL1-CL3 , form a classic Pi-L network and suppress
harmonic frequency emissions. This circuit is switched and tuned by S1A-S1C and the air variable
capacitors CP1, 2 and CL1, 2. The output signal is fed through the antenna relays K1 or K2 in the
WATTMETER PCB. The WATTMETER PCB also includes a high-pass filter for frequencies below 100 kHz,
and it prevents the plate supply from reaching the antenna.
The plate RF voltage is monitored through the capacitor Ca and together with the RF WATTMETER is the
main source of information for the control circuit of the amplifier in evaluating tuning quality. The control
circuit is based on the ATMEGA-8L micro-controller from Atmel. All voltages are delivered from the line
(mains) and HV PCBs. The currents of the control grid, screen grid, and the plate, as well as the reflected
power and tuning quality, etc., are continuously monitored by the micro-controller. Many software-derived
protections are based on this information.
* Detailed electrical schematic diagrams are available from ACOM or from your dealer on request.
Exhibit 6 page 14 of 15
Fig.5-1 ACOM1010 Simplified Schematic Diagram
Exhibit 6 page 15 of 15
6. SPECIFICATIONS
6-1. Parameters
a) Frequency Coverage: All amateur bands in the 1.8-29.7MHz frequency range; extensions and/or
changes on request.
b) Power Output: 700 W PEP or 500 W continuous carrier.
c) Intermodulation Distortion: Better than 35 dB below rated output.
d) Hum and noise: Better than 40 dB below rated output.
e) Harmonic Output Suppression: Better than 50 dB below rated output.
f) Input and Output Impedance:
- Nominal value: 50 Ohm unbalanced, UHF (SO-239) type connectors;
- Input circuit: broadband, VSWR less than 1.3:1, 1.8-30 MHz continuously (no tuning, no switching);
- Bypass path: VSWR less than 1.1:1, 1.8-30 MHz continuously, 200 W maximum;
- Output (antenna) impedance matching capability: VSWR up to 3:1 or higher.
g) RF Gain: 11dB typically, frequency response less than 1dB (50 to 70 W drive power for rated output).
h) Primary Power: 85-132 V/170-264 V ac (100, 110, 120, 200, 210, 220, 230 & 240 V nominal taps), +10%
-15% tol.), 50-60 Hz, single phase, 1200 VA.
i) Complies with CE safety and electromagnetic compatibility requirements as well as FCC-regulations (10 &
12 m band locks provided).
l) Size & Weight (operating): WxDxH: 406x315x150mm, 16kg (16x12.4x5.9 inches, 35.2Lbs).
m) Operating environments:
- Temperature range: 0 to +50 degrees Celsius;
- Humidity: up to 95% @ +35 degrees Celsius.
- Height: up to 3000 m above sea level without output deterioration.
6-2. Functions
a) Antenna Impedance Matching Process: aided by a plate-load True Resistance Indicator (TRI).
b) Two antenna outputs selectable by a button on the front panel.
c) Protections:
- Cover interlock for operator's safety;
- Inrush power-on current limited to the nominal consumption;
- Control grid, screen grid, and plate currents;
- T/R sequencing;
- Antenna relay contacts, including RF power induced in antenna from another nearby transmitter;
- Antenna matching quality;
- Reflected power.
e) LED bar-graphs for forward peak power and reflected power.
h) Tube: a single Svetlana 4CX800A (GU74B) high-performance ceramic-metal tetrode with plate
dissipation of 800 W, grid driven, forced air-cooling.
6-3. Storage and Shipment
CAUTION
Should it be necessary to ship the amplifier, use the original packing as described below.
Switch off the amplifier, pull the line (mains) plug out of the outlet, disconnect all cables from the rear panel
of the amplifier (remove the ground connection the last), and then pack the amplifier in its original carton.
a) Acceptable storage environment: The amplifier may be kept packed in a dry, ventilated and unheated
location (with no chemically active substances such as acids or alkalis) within the following environment
ranges:
- Temperature range: -40 to +70 degrees Celsius
- Humidity: up to 75% @ +35 degrees Celsius.
b) Shipping Size and Weight: WxDxH: 530x470x280mm, 18kg (21x18.5x11 inches, 39.6Lbs).
c) All types of transportation may be used, including storage in an aircraft baggage compartment at up to
12000 meters above sea level.