VSWR Trips With High Levels Of Modulation and
HighPower................................... 4-3
ImproperTuningandLoading................. 4-3
Antenna .................................. 4-3
OutputNetwork............................ 4-3
Symptom:RemoteControlFunctionsDoNotWork .... 4-3
PossibleCauses................................ 4-3
Remote/LocalSwitch........................ 4-3
RemoteControlImproperlyWired............. 4-3
RemoteControlUnitNotFunctioning.......... 4-3
RibbonConnectorsLoose.................... 4-3
CausesforaPAVolts/PAAmpsRatioChange ........ 4-3
No+20VoltstoPDMAmplifier.................. 4-3
ImpedanceChange ............................. 4-3
PAFailure.................................... 4-3
Troubleshooting AM Noise......................... 4-4
50/60Hz...................................... 4-4
AudioLinesareNormallyBalanced ............... 4-4
100/120Hz.................................... 4-4
300/360Hz.................................... 4-4
60kHz....................................... 4-4
RFINoiseonAudio ............................ 4-4
SECTION V
TRANSMITTER OVERALL
Introduction..................................... 5-1
Personnel Protection .............................. 5-1
PrinciplesOfOperation............................ 5-1
FET’SintheGATESSeries™.................... 5-1
PDMTheoryInBrief ........................... 5-1
PolyphaseTheory .............................. 5-1
Audio/PDMSignalFlow......................... 5-1
PDMLoop.................................... 5-3
RFPowerFlow................................ 5-3
Failsafe....................................... 5-3
ACPowerFlow................................ 5-3
High Voltage Power Supply ...................... 5-3
Introduction ............................... 5-3
Description................................ 5-3
Low Voltage Power Supply and IPA Power Supply. . . 5-6
Introduction ............................... 5-6
Description................................ 5-6
AirflowSensor................................. 5-6
Introduction ............................... 5-6
Description................................ 5-6
Section VI
Parts List
Introduction..................................... 6-1
SECTION A
OSCILLATOR (A16)
PrinciplesOfOperation............................ A-1
Replacement/Alignment ........................... A-1
FrequencyAdjustment........................... A-1
Troubleshooting the
RFOscillator ................................... A-1
Symptom:NoOutput ........................... A-1
OpenFuse/Lossof+20V..................... A-1
RFKILL.................................. A-1
Q1,Q2,CR1................................ A-1
U1,CR4...................................A-1
U2 .......................................A-1
U3 .......................................A-1
SECTION B
IPA (A5)
PrinciplesofOperation.............................B-1
IPATuningNetwork............................B-1
Replacement/Alignment............................B-1
IPA Tuning and Testing
Procedure......................................B-1
IPATuning................................B-1
OhmmeterTestingtheIPA .......................B-1
HandlingMOSFET’s..............................B-1
TestingMOSFET’s ...............................B-2
SECTION C
POWER AMPLIFIER A1 through A4
PrinciplesofOperation.............................C-1
PAToroids......................................C-1
Replacing a PA Module............................C-1
TroubleshootingthePABoards......................C-1
OhmmeterTesting..............................C-1
HandlingMOSFET’s..............................C-2
TestingMOSFET’s ...............................C-2
ReplacingPATransistors.........................C-2
ScopingtheRFDrive..............................C-2
RFDrivePhasingMeasurement.....................C-2
SECTION D
OUTPUT NETWORK
PrinciplesofOperation.............................D-1
AdjustmentProcedures.............................D-1
TuningAndLoadingControls.....................D-1
OutputNetworkColdTuning.....................D-1
ThirdHarmonicTrapL7-C4 ..................D-1
Bandpass Filter L2-C2 .......................D-1
TEENetwork-LoadandTune................D-1
L2SlidingTap .............................D-1
L1Tap....................................D-2
SECTION E
OUTPUT MONITOR (A18)
PrinciplesofOperation............................. E-1
Replacement/Alignment............................E-1
Troubleshooting..................................E-1
Symptom: Detector Null Reading Is High and Cannot
BeAdjustedToZero............................ E-1
BadLoadImpedance ........................E-1
SampleSignalMissing....................... E-1
SECTION F
PDM GENERATOR (A15)
PrinciplesOfOperation............................ F-1
Replacement/Alignment............................ F-1
TroubleshootingPDMGenerator..................... F-1
Symptom: No Pulses At J4, Causing Zero Power Out-
putfromtheTransmitter......................... F-1
PowerSetting .............................. F-1
LossofPlusandMinus15Volts............... F-1
PDMInterrupt.............................. F-1
DC/AudioFailure........................... F-1
Rev. X 888-2314-001 ix
WARNING: Disconnect primary power prior to servicing.
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