Harris DX 25U - Table 6-0. Troubleshooting the Transmitter; Default Chapter; Introduction; Troubleshooting

Section VI
Troubleshooting
6.1 Introduction
This section of the technical manual contains troubleshooting
procedures for the DX-25U.
Problems that could cause an OFF AIR situation and how they
relate to the front panel ColorStat™ indicators, including over-
loads and interlocks will be discussed first.
This section is a troubleshooting guide for the transmitter as a
system. For additional information related to an individual mod-
ule or board, refer to the section of the manual for that particular
board.
This section contains techniques and guidelines to assist the
engineer in isolating the problem more quickly. The engineer
using this section of the manual must have the proper test
equipment available and has a good working knowledge of the
transmitter and the operation of the individual modules and
boards.
Table 6-0. Troubleshooting the Transmitter
Section VI
Troubleshooting
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1
Symptom: Transmitter will not turn ON - No ColorStat™ panelindicatorsareilluminated.................. 6-6
PossibleCauses.......................................................................... 6-6
LossofACPower.................................................................... 6-6
Loss of +5V Supply on LED Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-6
LooseConnectors..................................................................... 6-6
Symptom: Transmitter will not turn on - all ColorStat™ panelindicatorsareilluminatedGreen. ............ 6-6
PossibleCauses.......................................................................... 6-6
+5BCircuitNotUpToOperatingVoltage................................................. 6-6
ContactorTurnOnLogicOnTheController............................................... 6-6
ContactorDriveCircuitry............................................................... 6-6
+30VDCFeedbackAuxiliarySignal..................................................... 6-6
240VACCoilVoltage................................................................. 6-6
OpenContactorCoilOnK1orK2....................................................... 6-6
Symptom: Transmitter will not turn on - one or more ColorStat™ panel indicators are illuminated RED. . . . . . 6-7
PossibleCauses.......................................................................... 6-7
Symptom: Transmitter will turn ON but immediately turns OFF - one or more ColorStat™ panel indicators illumi-
nate RED. The transmitter may try to turn on twice and a fault indicator illuminates AMBER then RED.. . . . . 6-7
PossibleCauses.......................................................................... 6-7
Symptom: Transmitter turns On (LOW, MEDIUM or HIGH buttons illuminate) but there is no power output and
no PA current is indicated. Supply voltage is indicated on the multimeter. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-7
PossibleCauses.......................................................................... 6-7
PATurn-OffCommandGivenToTransmitter.............................................. 6-7
Type4orType5Fault ................................................................ 6-7
PowerOutputIsSetToZero............................................................ 6-7
Symptom:Transmitterisrunning,butpowerislowerthannormal..................................... 6-7
PossibleCauses.......................................................................... 6-7
PowerReductionCircuitryActivated..................................................... 6-7
Symptom: Unable to raise power past a certain point. ColorStat™ panel ANT and/or FILTER LED indicate RED. . 6-8
Possiblecause ........................................................................... 6-8
Symptom: Unable to raise power past a certain point. No ColorStat™ panel indicators Illuminated RED. . . . . . 6-8
Possiblecause ........................................................................... 6-8
Analog Input Board maximum power adjustment R27 misadjusted or defective. . . . . . . . . . . . . . . . . . . 6-8
Analog Input Board, half power step up circuit may have failed. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-8
PA Turn on/Turn Off control signals on Modulation Encoder A37 may be incorrect.. . . . . . . . . . . . . . . 6-8
OpenfusesonFuseBoardsA24orA25................................................... 6-8
Symptom: Transmitter turns ON (Low, Medium, or High Indicators Illuminate) but will not modulate. . . . . . . . 6-8
Rev. R: 11-11-96 888-2297-002 6-1
WARNING: Disconnect primary power prior to servicing.