UBS Axcera 840A 10,000-watt UHF solid state television transmitter User Manual Chapter 2

UBS-Axcera 10,000-watt UHF solid state television transmitter Chapter 2

Chapter 2

10-kW UHF Transmitter with Chapter 2, System DescriptionFeedforward Driver840A, Rev. 0 2-1Chapter 2System DescriptionThe 840A (1064941) is a complete 10-kW UHF internally diplexed televisiontransmitter that operates at a nominalvisual output power of 10,000 watts peaksync visual and an average aural outputpower of 1000 watts with a 10 dBaural/visual ratio.2.1 System OverviewThe 840A is made up of three cabinetassemblies: the (A1) dual 250-wattdriver/amplifier assembly (1064946);(A2) the 10-kW amplifier assembly(1299-1100); and (A3) the high-voltagepower supply assembly, 208/240 VAC(1068022).2.1.1 (A1) Dual 250-WattExciter/Amplifier Assembly(1064946; Appendix A)The dual 250-watt driver/amplifierassembly is made up of the assembliesand trays shown in Table 2-1.Table 2-1. Driver/Amplifier Assembly Assemblies and TraysDESIGNATION NUMBER TRAY/ASSEMBLY NAME DRAWING NUMBERA2 AC distribution assembly 1265-1600A4 UHF exciter tray 1063301A9 3-watt amplifier tray 1068203A6 and A7 250-watt amplifier trays 1044027, low-band;1044028, mid-band;1044029, high-bandA14 Bandpass filter assembly --The exciter/amplifier assembly(1064946) is connected to the basebandvideo and aural inputs. The assemblyalso provides connections for the remotemonitoring and operation of theexciter/amplifier assembly. The UHFexciter tray (1063301) takes thebaseband aural and video inputs andproduces the visual and aural RF signalson the channel frequencies. Thecombined visual and aural RF output (+7dBm) of the exciter feeds the 3-wattamplifier tray (1068203). The 3-wattamplifier tray contains an automatic gaincontrol circuit and two 3-watt amplifierboards. The tray generates the outputlevel needed to drive the 250-wattamplifier trays (1044027, low-band;1044028, mid-band; and 1044029, high-band).The output from the 3-watt tray is fed tothe (A10) RF hybrid splitter SMAconnection J1. The RF hybrid splitteroutput feeds the RF signal to one of the250-watt amplifiers directly and, through(A5) the line stretcher, to the other 250-watt amplifier. The line stretcher givesthe operator the ability to control thephase of the output signal that is fed toone of the 250-watt trays. Each of the250-watt amplifier trays contains anamplifier enclosure and feedforwardcircuits to achieve an output of 250-wattspeak visual power and 25 watts of auralpower.In the 250-watt amplifier tray, a forwardpower sample from the UHF coupler isconnected to the dual peak detectorboard; this board provides a peak-detected forward sample to the amplifiercontrol board for metering purposes.Before exiting the 250-watt amplifiertray, the RF is fed through a circulator forthe protection of the tray from highVSWR conditions. The reject port of thecirculator is cabled to the reject
10-kW UHF Transmitter with Chapter 2, System DescriptionFeedforward Driver840A, Rev. 0 2-2load/coupler board; this board suppliesthe reflected sample to the dual peakdetector board, single supply. This signalis then sent to the amplifier control boardfor metering purposes. The output of the250-watt visual amplifier trays iscombined in a UHF tee combiner, and fedthrough (A14) a bandpass filter and(A11) a directional coupler, before beingconnected with1/2" heliax to the RF inputjack (A2-A1-J1) of the tube cavityassembly in the 10-kW amplifierassembly cabinet. The combined outputof the 250-watt visual amplifier trays(350 watts) is the level needed to drivethe 10-kW amplifier to 10,000 wattspeak sync visual output.The main AC input to theexciter/amplifier assembly is (A2) the ACdistribution panel assembly (1265-1600).The AC distribution panel assemblycontains a terminal block (TB1) thatconnects to the main AC input (208/240VAC). The terminal block has four metal-oxide varistors (MOVs) connected acrossthe input lines for surge and transientprotection. The AC distribution panelcontains CB1, the 40-amp main ACcircuit breaker that distributes the ACthrough the circuit breakers CB2 to CB7to the exciter and amplifier trays.2.1.2 (A2) 10-kW Diacrode Amplifier(1299-1100; Appendix A)The (A11) metering control panel (1293-1308) on the amplifier assembly providesthe operator with front panel meteringfor all voltage (M1 using S1) and current(M2 using S3) readings that apply to thetube. The metering control panel alsoprovides the aural, visual, and reflectedoutput power readings for the transmitterusing meter M3 with switch S4. The frontpanel assembly contains the switchesthat control the Operate/Standby (S5)and Automatic/Manual (S6) operation ofthe 10-kW amplifier. When switched toOperate, the panel supplies the driverenable (Operate command) to theexciter/amplifier assembly. TheAutomatic/Manual switch selects eitherthe automatic operation of thetransmitter, which uses the video inputto control the on/off state of thetransmitter, or the Normal front panelcontrol, manual operation, of thetransmitter. The metering control panelalso provides front panel control, throughswitch S8, of the Visual Output Powerlevel. High-Voltage Enable/Disable switchS7 controls the high-voltage powersupply from the front panel of the 10-kWdiacrode amplifier. Normal/Exciter Testswitch S10, when in the Exciter Testposition, gives the operator the ability tooperate the exciter/amplifier assemblywithout operating the 10-kW amplifier.Note: The exciter/amplifier assemblyoutput must be terminated into adummy load prior to using thisfunction.The metering control panel also has LEDson the front panel for a visual indicationof the operating status of thetransmitter: Operate/Standby,Auto/Manual, High VoltageEnable/Disable, Driver ModeNormal/Test, 3-Fault with Fault ResetSwitch (S9), Fault Status Overtemp, andVSWR Cutback. The front panel hascommand status LEDs that indicate,when they are lit, that the command hasbeen given. In addition, the front panelhas Operate status LEDs that indicate,when they are lit, that the command hasbeen carried out.The metering control panel of the (A10)remote control and cabinet interfaceassembly provides intercabinet controland monitoring for the exciter and high-voltage cabinets. The remote control andcabinet interface assembly also providesremote access to the transmitter formonitoring and control purposes.The (A6) screen power supply assembly,60 Hz (1293-1321), in the rearcompartment of the amplifier cabinet,produces the 500 VDC at 60 mA for thetube. The (A5) control and bias powersupply assembly (1181-1402) contains
10-kW UHF Transmitter with Chapter 2, System DescriptionFeedforward Driver840A, Rev. 0 2-3two separate power supplies: the controlpower supply and the bias power supply.The control power supply produces the±12 VDC to the metering circuits (peakdetectors) in the 10-kW amplifier as wellas the fault sensing boards, differentialbuffer boards, and control logic boards inthe metering control panel. The biaspower supply produces the -80 VDC biasvoltage to the tube. R1, the bias voltageadjustment, is located behind themetering control panel. It sets up theidling current (1.5 amps), no RF drive, byadjusting the bias voltage. The (A3)filament power supply assembly (1299-1107) produces the 5.2 VDC to thefilament of the tube. The 10-kWassembly also has (A16) a blowerassembly (1293-1325) that provides thecoolant air flow to the tube mounted inthe cavity assembly.The RF output of the 10-kW amplifier at(A2-A1-J2) is fed through a 3-1/8"hardline to (A2) an output coupler (1020-1043) that provides a reflected powersample for fault and VSWR cutbackprotection. The output at (A2-A2-J2)connects to two UHF trap filters. The trapfilters screen out the -3.58-MHz, -4.5-MHz, +8.08-MHz, and +9.00-MHzintermodulation products as well as thesecond visual harmonic frequency. Theoutput of the trap filter is fed through(A18) the output coupler (1020-1002)that provides a reflected and forwardpower sample to (A19) the visual/auralmetering assembly (1162-1402) formetering purposes. The output of thecoupler is then fed to the antenna.The visual/aural metering assemblyconsists of (A1) a single peak detectorboard (1162-1403) for the reflectedoutput metering. It also contains (A2) avisual/aural metering board (1161-1103or 1161-1115) for aural output and visualoutput power levels and reflected powerlevel for VSWR protection.2.1.3 (A3) High-Voltage PowerSupply Assembly, 208/240 VAC(1068022; Appendix A)The (A3) high-voltage power supplyassembly, 208/240 VAC (1068022),provides the 10-kW amplifier, throughTB4, with the AC voltage that theassembly needs to operate. It alsosupplies the AC needed to operate theblower assembly, through TB6, and thehigh-voltage, using 18 AWG 29-kVrubber insulated wires, needed tooperate the tube in the 10-kW amplifier.The high-voltage power supply producesthe 5000 VDC at 4.00 amps, maximumcurrent (black picture), or 1.5 ampsidling current (no RF drive applied) forthe plate (anode) of the tube. Theassembly contains (A1) the high-voltagetransformer (1293-6103), (A5, A6, andA7) the three high-voltage rectifierboards (1293-1101), (A8, A19, A22, andA23) filter capacitors, and (A16) thechoke that generate the high voltage.The high-voltage power supply assemblyalso contains the power supply meteringboards, the isolation relay boards, thecircuit breakers needed to supply high-voltage metering, high voltage-on sense,the power-on sequence, the switching onand off, and the protection of the highvoltage. The high-voltage power supply,at TB2, is connected to the 10-kWassembly that provides the +12 VDC formetering, switching, and the Enable tothe high-voltage power supply.2.1.4 (A19) Visual/Aural MeteringAssembly (1162-1402; Appendix A)The visual/aural metering assembly takesthe forward and reflected power samplesfrom the (A2-A2) and the (A18) outputcouplers. The assembly provides themetering control panel on the front panelmeters with visual, aural, and reflectedlevels for remote monitoring and VSWRprotection.The visual/aural metering assemblyconsists of (A1) a single peak detectorboard (1162-1403) for the reflected
10-kW UHF Transmitter with Chapter 2, System DescriptionFeedforward Driver840A, Rev. 0 2-4output metering. It also contains (A2) avisual/aural metering board (1161-1103or 1161-1115) for aural output and visualoutput power levels and reflected powerlevels for VSWR protection.2.2 Control and StatusInformation on the control and status ofthis system is provided by control,status, and LED indicators and meters onthe front panel of the trays. The functionsof these control and status indicators aredescribed in the following tables.2.2.1 Exciter/Driver Cabinet2.2.1.1 UHF Exciter TrayTable 2-2. UHF Exciter Tray MetersMETER FUNCTIONReads power in terms of a percentage of the calibrated outputpower level on the upper scale. The voltage level or frequencylevel is read on one of the two bottom scales. A full-scalereading on the top scale is 120%; 100% is equivalent to thefull-rated 350 watts peak of sync visual. This meter also reads% Aural Power, % Exciter Power, audio levels, video levels, andALC levels.With Switch S3 inPosition DisplaySwitch (S3), MeterSelects the desired ALC voltagereading, % Exciter Power, % VisualPower, % Aural Power, video levels, oraudio levels.AudioReads the audio level, ±25 kHzbalanced or ±75 kHz composite, onthe 0 to10 (0 to100 kHz) scale.Indicates baseband audio if it isconnected to the transmitter and evenwith the video + 4.5 MHz SCA inputselected.ALC(0 to 10 V) Reads the ALC voltage level, .85VDC, on the 0 to10 scale% Exciter(0 to 120)Reads the % Exciter Output Powerlevel needed to attain 100% output ofthe transmitter on the top scale% Aural Power(0 to 120)Reads the % Aural Output Power ofthe exciter/driver assembly(100%=45 watts at 10 dB A/V ratio)on the top scale% Visual Power(0-120)Reads the % Output Power of theexciter/driver assembly (100%=450watts peak sync) on the top scaleMeter (A4-A18)Video(0-1V) Reads the video level, 1V at white, onthe 0-10 scale
10-kW UHF Transmitter with Chapter 2, System DescriptionFeedforward Driver840A, Rev. 0 2-5Table 2-3. UHF Exciter Tray Control SwitchesSWITCH FUNCTIONTransmitter (S1)Operate/StandbyThe momentary switch (S1) applies aground to K1, a latching relay on thetransmitter control board. K1 will switcheither to Operate or to Standby, dependingon which direction S1 is pushed. Whenswitched to Operate, the low Enablecommands are applied to the four UHFamplifier trays. The opposite occurs whenS1 is switched to Standby.Mode Select (S2)Auto/ManualThe momentary switch (S2) applies aground to K2, a latching relay on thetransmitter control board. K2 will switch thetransmitter to Automatic or Manual,depending on which direction S2 is pushed.In Automatic, the Video Fault commandfrom the ALC board will control theoperation of the transmitter. Thetransmitter will switch to Standby, after aslight delay, if the video input is lost andwill switch back to Operate, quickly, whenthe video is restored. In Manual, thetransmitter is controlled by the operatorusing the front panel Operate/Standbyswitch or by remote control.Power Adjust (R1) The 5 kΩ pot, A20, sets the ALC level onthe ALC board. This sets the output powerfor the transmitter.Table 2-4. UHF Exciter Tray Fault IndicatorsFAULT INDICATOR FUNCTIONVideo Loss (DS9 Red)Indicates that the video input to thetransmitter has been lost. The fault isgenerated on the ALC board in the UHFexciter tray.VSWR Cutback (DS7 Amber)Indicates that the reflected power level ofthe 10-kW transmitter has increased above15%. This will automatically cut back theoutput power level to 15%. The fault isgenerated on the transmitter control boardin the UHF exciter tray and is derived froma peak-detected voltage in the amplifiercabinet.
10-kW UHF Transmitter with Chapter 2, System DescriptionFeedforward Driver840A, Rev. 0 2-6Table 2-5. UHF Exciter Tray SamplesSAMPLE DESCRIPTIONf(IF) A sample of the visual IF that is taken fromthe sample jack on the IF carrier ovenoscillator boardf(IC) A sample of the intercarrier signal that istaken from the sample jack on the aural IFsynthesizer boardf(s) A sample of the channel oscillator outputthat is taken from the sample jack of thechannel oscillator assemblyExciter O/P An output power sample of the exciter thatis taken from the UHF upconverter board2.2.2 3-Watt Amplifier TrayTable 2-6. 3-Watt Amplifier Tray MeterMETER FUNCTIONSelects whether the % Reflected Power, % Input Power, %Forward Power, power supply voltage, or AGC voltage is to beviewed on the meterWith Switch S1 in position Display% Refl (Reflected) Reads the % Reflected OutputPower (<10%)% Input Reads the % Input Power tothe tray (10%)% Forward Power Reads the % Forward Power(100%=3 watts CW)P.S. Voltage Reads the power supplyvoltage (+24 VDC)Power Meter, Switch(S1)AGC Voltage Reads the AGC voltage(2 VDC)Table 2-7. 3-Watt Amplifier Tray Fault IndicatorsFAULT INDICATOR FUNCTIONOvertemp (DS1)Indicates that the temperature of theheatsink, where the Q1 and Q2 current-pass transistors for the +24 VDC powersupply are mounted, is above 175° F assensed by the thermal switch (S2) mountedto the heatsink. When this fault occurs, theEnable to the isolation relay is removedimmediately.AGC Override (DS2)Indicates that the level out of the 3-wattamplifier board has requested the AGCcircuit to exceed the AGC limits. The fault isgenerated on the AGC board in the 3-wattamplifier tray.
10-kW UHF Transmitter with Chapter 2, System DescriptionFeedforward Driver840A, Rev. 0 2-72.2.3 250-Watt Amplifier TraysTable 2-8. 250-Watt Amplifier Tray MetersMETER FUNCTIONReads power in terms of a percent of the calibrated poweroutput value. A full-scale reading is 100%, which is equivalentto the full-rated 250 watts peak of sync visual + aural outputpower. Also reads % Reflected Power, power supply voltagelevels, and AGC voltage levels.With Switch S1 inPosition DisplaySwitch (S1), Meter Selects the desired % Power or thevoltage reading% Output PwrReads the % Output Power of thetray (100%=250 watts peak of syncvisual with -10 dB aural on the topscale)% Refl (Reflected) Reads the % Reflected Output Powerof the tray (<10%)Meter (A12)Power Supply Reads the power supply voltage,+26.5 VDC, on the middle scaleTable 2-9. 250-Watt Amplifier Tray Status IndicatorsSTATUS INDICATOR FUNCTIONEnable (DS1 Green) Indicates that an Enable, Operate,command, is applied to the UHF amplifiertray from the selected UHF exciter trayOvertemp (DS2 Red)Indicates that the temperature of (A1-A7and A1-A8), one or both of the two thermalswitches mounted on the heatsink assemblyfor the output amplifiers, is above 175° F.When this fault occurs, the Enable to theswitching power supply in the affectedamplifier tray is removed immediately andwill shut down.
10-kW UHF Transmitter with Chapter 2, System DescriptionFeedforward Driver840A, Rev. 0 2-82.2.4 10-kW Amplifier Assembly Metering Control PanelTable 2-10. 10-kW Amplifier Assembly MetersMETER FUNCTIONReads DC voltage (a full-scale reading is 1 volt) Note: A multiplier,whose value is dependent on which position switch S1 is in,must be applied. The multiplier that is needed is marked inparentheses near the switch.With Switch S1 inPosition DisplaySwitch (S1) Voltage Meter Selects the desired plate voltage,screen voltage, bias voltage, andfilament voltage readingsPlate (x10 k) Reads the plate voltage (typicalreading is 5200 volts)Screen (x1 k) Reads the screen voltage (typicalreading is 500 volts)Bias (x1 k) Reads the bias voltage (typicalreading is 85 volts)Voltage Meter(M1)Filament (x10) Reads the filament voltage (typicalreading is 5.2 volts; black heatvoltage is 1.5 volts)Reads DC current (a full-scale reading is 50 mA) Note: Amultiplier, whose value is dependent on which positionswitch S2 is in, must be applied. The multiplier that is neededis marked in parentheses near the switch.With Switch S2 inPosition DisplaySwitch (S2), CurrentMeterSelects the desired plate current,screen current, and control gridcurrent readingsPlate (x100)Reads the plate current (atypical reading is 1.5 amps, noRF drive, to 4 amps; 100%power, sync-only)Screen (x2) Reads the screen current (typicalreading is <60 mA)Current Meter(M2)Control Grid (x1)Reads the control grid current(typical reading is 0 mA to 5 mA)Note: The meter reverseswitch (S3) must be switcheddown to give an upscalereading.
10-kW UHF Transmitter with Chapter 2, System DescriptionFeedforward Driver840A, Rev. 0 2-9METER FUNCTIONReads power in terms of a percent of the calibrated power value (afull-scale reading will be 100%)With Switch S4 inPosition DisplaySwitch (S4), Power MeterSelects the desired visual outputpower, aural outputpower and the reflectedoutput power readingsVisual Output Reads the visual output power of the 10-kW amplifier (100%)Aural Output Reads the aural output power of the10-kW amplifier (100%)Power Meter(M3)Reflected Reads the reflected visual outputpower from the 10-kW amplifier(<10%)Table 2-11. 10-kW Amplifier Assembly SwitchesSWITCH FUNCTIONMeter Polarity (S3)Changes the polarity of the measuredcurrent applied to the meter. To properlyread the plate I and screen I, the meterpolarity switch must be in the Up (+)position to give an upscale reading. To readthe control grid I properly, the switch mustbe in the Down (-) position. The normalsetting of the meter reverse switch is theUp position.Transmitter (S5)The momentary switch (S5) applies aground to K3, a latching Operate/Standbyrelay on (A7) the transmitter control board.K3 switches either to Operate or to Standbydepending on which direction S5 is pushed.When S5 is switched to Operate, a lowOperate (Enable) command is applied to(A1) the control logic board to start theautomatic turn-on procedure for the 10-kWtransmitter. The opposite occurs when S5 isswitched to Standby.Mode Select (S6)The momentary switch (S6) applies aground to K1, a latching Auto/Manual relayon (A7) the transmitter control board. K1switches the transmitter to Automatic orManual depending on which direction S6 ispushed. In Automatic, a video faultcommand from the upconverter traycontrols the transmitter. The transmitterswitches to Standby if the video input is lostand will switch to Operate when the video isreapplied. In Manual, the transmitter iscontrolled through the normal automatic
10-kW UHF Transmitter with Chapter 2, System DescriptionFeedforward Driver840A, Rev. 0 2-10SWITCH FUNCTIONturn-on sequence with the operator usingthe front panel controls or remotecontrol.HV (High Voltage) (S7)Enable/DisableWhen the switch is enabled (Up), themagnetic latching relay (K1) on (A1) thecontrol logic board will engage. The high-voltage enable indicator will light along withthe High-Voltage Request LED. The High-Voltage On command to the high-voltagerelay will be applied at the proper timeduring the automatic turn-on sequence.When switched to Disable, the High-VoltageOn command will be removed, disabling thehigh voltage and causing the Automatic OffCycle sequence to occur.Output Power (S8)Adjusts the output power level of thetransmitter by raising or lowering the ALClevel on the visual ALC/AGC board in theUHF exciter tray. This control is used tocompensate for the small, everydayvariations in the output power level. If amajor variation occurs, a problem exists.After the problem has been repaired, theoutput power level adjustment may alsorequire a readjustment to the AGCvoltage levels (refer to the system setupprocedures in Chapter 3 of this manual).Fault Reset (S9)As a fault occurs in the transmitter, theFault LED will flash on and then go off asthe transmitter automatically resets itselfto try to eliminate the problem. If theproblem remains, the transmitter will try toreset itself three times in approximately oneminute. After this, the Three-Fault indicatorwill remain lit and the transmitter willautomatically shut down. When the problemthat caused the fault is found and repaired,the Fault Reset switch S9 must be setbefore the transmitter will recycle.Driver Mode (S10)Normal/TestWhen the switch is in Normal (Up), thetransmitter operates normally. When theswitch is in Test (Down), the magneticlatching relay (K4) on (A7) the transmittercontrol board supplies the driver Enable tothe exciter/driver assembly. This allows theoperation of the exciter/driver assemblywithout requiring the 10-kW amplifiersection to be on. When this function isbeing performed, the driver must beterminated into a dummy load and the highvoltage must be disabled.
10-kW UHF Transmitter with Chapter 2, System DescriptionFeedforward Driver840A, Rev. 0 2-11Note: The circuit breakers discussedin Table 2-12 are on the ACdistribution panel of the 10-kWamplifier and the high-voltage powersupply assembly. For the othercircuit breakers on the panel tooperate, the main AC and the controlcircuit breakers must both beswitched on.Note: When the preceding commandis completed, the automatic turn-onprocedure will cycle the transmitterthrough the command status andcorresponding operating status stepsfrom left to right on the front panelLEDs. The Command Status indicatorshows that a command has beengiven and the Operating Statusindicator shows that the commandhas been carried out.Table 2-12. 10-kW Amplifier Assembly Command Status IndicatorsSTATUS INDICATOR FUNCTIONBlower (DS8)Indicates that the Blower On command(Enable) has been given by the controllogic. The blower is controlled by thefilament power supply control board thatsends a low Enable command to theisolation relay on the blower assembly. Therelay energizes and the closed contactsapply 220 VAC to the blower contactor K1.If the blower circuit breaker is turned on,the 208/240 VAC 3 phase is applied to (A1)the blower and the unit will operate.Filament (DS9)Indicates that the blower is on and that theFilament On command (Enable) has beengiven to the filament power supplyassembly. If the black heat has beenapplied to the filament for at least 10minutes, the Operate command activatesthe ramp-up phase of the filament powersupply.Bias (DS10)Indicates that the filament voltage has beenat 5.2 volts for approximately 20 secondsand the Bias On command (Enable) hasbeen given to the isolation relay (A3) on thecontrol and bias power supply assembly.The relay energizes and, when the biascircuit breaker is turned on, applies 220VAC to the bias power supply board.High Voltage (DS11)Indicates that the bias voltage is on and theHigh Voltage On command (Enable) hasbeen given to the isolation relay (A24)in the high-voltage power supply assembly.The relay energizes and applies +12 VDC tothe (A18) isolation relay and (K1) thecontactor control relay that control the
10-kW UHF Transmitter with Chapter 2, System DescriptionFeedforward Driver840A, Rev. 0 2-12STATUS INDICATOR FUNCTIONstep-start and high-voltage contactors.When the main AC and HV circuit breakersare turned on, 208/240 VAC is applied tothe transformer of the high-voltage powersupply.Screen (DS12)Indicates that the high voltage (platevoltage) is on and the Screen On command(Enable) has been given to the isolationrelay (A7) mounted in the screen powersupply assembly. The relay energizes and,when the screen circuit breaker is switchedon, applies 220 VAC through the Sola 60 Hzregulator to the transformer (T1) that ispart of the screen power supply.RF Request (DS13)Indicates that the tube has all of thevoltages applied and that the RF Oncommand (Enable) has been given toenable the exciter/driver assembly thatapplies the RF drive to the 10-kW amplifierTable 2-13. 10-kW Amplifier Assembly Operating Status IndicatorsSTATUS INDICATOR FUNCTIONBlower (DS16)Indicates that the blower is on. Thequantity of air flow through the exhauststack is measured by the air pressuresensor.Filament (DS17)Indicates that the above step is completeand that the filament voltage is on. This isindicated when the filament voltage onsense at J12-11 of the control logic board islow.Bias (DS18)Indicates that the above steps are completeand the bias voltage is on. This is indicatedwhen the bias on sense at J13-2 of thecontrol logic board is low.High Voltage (DS19)Indicates that the above steps are completeand the high voltage is on. This is indicatedwhen the high voltage on sense at J13-8 ofthe control logic board is low.Screen (DS20)Indicates that the above steps are completeand the screen voltage is on. This isindicated when the screen voltage on senseat J13-14 of the control logic board is low.RF Present (DS21)Indicates that the above steps are completeand that there is an RF output from thetransmitter. This is indicated when there isa forward power sample fed to (J15 - 7 and6) of the transmitter control board.
10-kW UHF Transmitter with Chapter 2, System DescriptionFeedforward Driver840A, Rev. 0 2-13Table 2-14. 10-kW Amplifier Assembly Fault IndicatorsFAULT INDICATOR FUNCTIONOver Temp (DS22)Indicates that the air temperature in theexhaust stack is above 200° F as sensedby the thermal switch (A15-S1) mountedthere. When this fault occurs, the voltageswill be immediately removed from the tube,but the blower will continue running tocool the transmitter.VSWR Cutback (DS23)Indicates that the reflected output powerof the transmitter, as sampled at (J15 - 1and 2) of the transmitter control board, hasexceeded 10%; this causes the 10-kWamplifier to cut back the output power levelneeded to maintain a 10% visual reflectedlevel. If the reflected output power levelexceeds 15%, a VSWR fault will occur andcause the transmitter to shut down.
10-kW UHF Transmitter with Chapter 2, System DescriptionFeedforward Driver840A, Rev. 0 2-142.3 Remote Control InterfaceConnectionsThe remote control interfaceconnections for the 840Atransmitter are listed in thefollowing tables.Table 2-15. 10-kW Amplifier Assembly Remote Control Interface ConnectionsFUNCTION REMOTE JACK/PINNUMBER INTERFACE TYPEInterlock (Total Shutdown) J1-1Interlock (Total Shutdown)Rtn J1-2May be connected to aremote interlockInterlock (Drv, Scrn, andhigh voltage) J1-3Interlock (Drv, Scrn, andhigh voltage) Rtn J1-4May be connected to aremote interlockNote: The jumper plug (1176-1019), with jumpers connected between pins 1and 2 and 3 and 4, must be plugged into jack (J1) for the normal operation ofthe transmitter.Remote Status IndicationsTransmitter Operate Ind J4-1 50 mA max current sinkTransmitter Operate Rtn J4-2Transmitter Auto Mode Ind J4-3 50 mA max current sinkTransmitter Auto Mode Rtn J4-4High Voltage Enable Ind J4-5 50 mA max current sinkHigh Voltage Enable Ind Rtn J4-6Fault Ind J4-7 50 mA max current sinkFault Ind Rtn J4-8RF Present Ind J4-9 50 mA max current sinkRF Present Ind Rtn J4-10Overtemp Ind J4-11 50 mA max current sinkOvertemp Ind Rtn J4-12VSWR Cutback Ind J4-14 50 mA max current sinkVSWR Cutback Ind Rtn J4-15Video Fault Ind J4-16 50 mA max current sinkVideo Fault Ind Rtn J4-17
10-kW UHF Transmitter with Chapter 2, System DescriptionFeedforward Driver840A, Rev. 0 2-15FUNCTION REMOTE JACK/PINNUMBER INTERFACE TYPERemote CommandsOperate Cmd J5-1 Contact closureOperate/Standby Cmd Rtn J5-2Standby Cmd J5-3 Contact closureAuto Mode Select Cmd J5-4 Contact closureAuto/Manual Select Cmd Rtn J5-5Manual Select Cmd J5-6 Contact closureH.V. Enable Cmd J5-7 Contact closureH.V. Enable/Disable CmdRtn J5-8H.V. Disable Cmd J5-9 Contact closurePower Raise Cmd J5-10 Contact closurePower Raise/Lower Cmd Rtn J5-11Power Lower Cmd J5-12 Contact closureFault Reset Cmd J5-13 Contact closureFault Reset Rtn J5-14Remote MeteringReflected Power Metering J6-1Reflected Power Rtn J6-2 1V full scale at 1 kΩ sourceresistanceVisual Forward PowerMetering J6-3Visual Forward Power Rtn J6-41V full scale at 1 kΩ sourceresistancePlate Current Metering J6-5Plate Current Rtn J6-6 1V full scale at 1 kΩ sourceresistanceScreen Current Metering J6-7Screen Current Rtn J6-8 1V full scale at 1 kΩ sourceresistanceControl Grid CurrentMetering J6-9Control Grid Current Rtn J6-101V full scale at 1 kΩ sourceresistancePlate Voltage Metering J6-11Plate Voltage Rtn J6-12 1V full scale at 1 kΩ sourceresistanceScreen Voltage Metering J6-13Screen Voltage Rtn J6-14 1V full scale at 1 kΩ sourceresistanceBias Voltage Metering J6-15 1V full scale at 1 kΩ sourceresistance
10-kW UHF Transmitter with Chapter 2, System DescriptionFeedforward Driver840A, Rev. 0 2-16FUNCTION REMOTE JACK/PINNUMBER INTERFACE TYPEBias Voltage Rtn J6-16Filament Voltage Metering J6-17Filament Voltage Rtn J6-18 1V full scale at 1 kΩ sourceresistanceAural Forward PowerMetering J6-20Aural Forward Power Rtn J6-211V full scale at 1 kΩ sourceresistanceNote: The remote control interface connections for the 10-kW amplifier connectto jacks J1, J4, J5, and J6 of (A10) the remote control and cabinet interfaceassembly mounted to the rear and at the top of the amplifier cabinet.The remote connections listed in Table 2-16 are only made if the (A12) A/V inputand remote interface assembly arepresent in the system. The remoteconnections are made to jacks J9 and J10on the assembly. Refer to theinterconnect drawing (1064945) for theproper pin remote connections.Table 2-16. UHF Exciter Remote Control Interface ConnectionsFUNCTION REMOTE CONTROL/PINNUMBER INTERFACE TYPETransmitter Enable Interlock J9-21Transmitter Enable InterlockRtn J9-22J9-21 and 22 must bejumpered together fornormal operation; (1176-1038) jumper jack shouldbe usedRemote Control CommandsTransmitter Standby(Disable) J9-9 Contact closureTransmitterStandby/Operate Rtn J9-10Transmitter Operator(Enable) J9-11 Contact closureTransmitter Manual J9-15 Contact closureTransmitter Auto/ManualRtn J9-16Transmitter Auto J9-17 Contact closurePower Level Raise (optional) J9-27 Contact closurePwr Lvl Raise/Lower Rtn(optional) J9-28Power Level Lower(optional) J9-29 Contact closureModulator Select (optional) J9-31 Contact closure
10-kW UHF Transmitter with Chapter 2, System DescriptionFeedforward Driver840A, Rev. 0 2-17FUNCTION REMOTE CONTROL/PINNUMBER INTERFACE TYPEModulator Select Rtn(optional) J9-32Remote Status IndicationsTransmitter Operate(Enable) Ind J9-12 50 mA max current sinkOperate/Standby Ind Return J9-13Transmitter Standby(Disable) Ind J9-14 50 mA max current sinkTransmitter Auto Indicator J9-18 50 mA max current sinkAuto/Manual IndicatorReturn J9-19Transmitter ManualIndicator J9-20 50 mA max current sinkVSWR Cutback Indicator J9-23 50 mA max current sinkVSWR Cutback IndicatorReturn J9-24Video Loss (Fault) Indicator J9-25 50 mA max current sinkVideo Loss (Fault) Ind Rtn J9-26Receiver Fault (optional) J9-30Remote MeteringReflected Power J9-5Reflected Power Rtn J9-6 1V full scale at 1 kW sourceresistanceExciter Output Power J9-7Exciter Output Power Rtn J9-8 1V full scale at 1 kW sourceresistance
10-kW UHF Transmitter with Chapter 2, System DescriptionFeedforward Driver840A, Rev. 0 2-18Table 2-17. UHF Amplifier Tray Remote Control Interface ConnectionsFUNCTION REMOTE JACK/PINNUMBER INTERFACE TYPEMetering3-watt Fwd Pwr Mtrg J10-16 1V at 1KΩ source resistance3-watt Fwd Pwr Mtrg Rtn J10-17 1V at 1KΩ source resistance250-watt amp A7 Fwd PwrMtrg J10-6 1V at 1KΩ source resistance250-watt amp A7 Fwd PwrMrtg Rtn J10-7 1V at 1KΩ source resistance250-watt amp A7 Refl PwrMtrg J10-8 1V at 1KΩ source resistance250-watt amp A7 Refl PwrMtrg Rtn J10-9 1V at 1KΩ source resistance250-watt amp A6 Fwd PwrMtrg J10-1 1V at 1KΩ source resistance250-watt amp A6 Fwd PwrMtrg Rtn J10-2 1V at 1KΩ source resistance250-watt amp A6 Refl PwrMtrg J10-3 1V at 1KΩ source resistance250-watt amp A6 Refl PwrMtrg Rtn J10-4 1V at 1KΩ source resistanceNote: These remote connections are made only if the optional (A12) A/V inputand remote interface assembly are present in the system. The remoteconnections are made to jacks J9 and J10 on the assembly. Refer to theinterconnect drawing (1064945) for the proper pin remote connections.

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