GPH-CMD VHF Radio
Maintenance
BK RADIO
Page 5-15
5.6 TROUBLESHOOTING
Radio Will Not Transmit
Red LED Does Not Light
-Invalid TX frequency programmed
-Weak battery
-VCO TX bandshift circuit failing
-Open PTT path
-Broken PTT switch
Radio Will Not Turn On
-Exhausted battery
-Open fuse
-Broken ON/OFF switch
-Failing 5-volt regulator
-Improper information in EEPROM
Radio Will Not Unmute
-Invalid RX frequency programmed
-Internal squelch trimmer adjusted improperly
-CAR PRES signal to microprocessor shorted or
open
-Audio amplifier failing
-DISC AUDIO path open or shorted
-RX AUDIO path open or shorted
Transmit Power Below Specification
-Software power adjustment incorrect
-RF side connector jack failing
-Harmonic filter failing
-Power amplifier failing
-Power control circuit failing
-Antenna switch failing
-VCO buffer failing
Code
Guard Signal Not Being
Transmitted
-No Code Guard signal programmed on transmit
channel
Poor Battery Life
-Weak or defective battery
-Transmitter power adjusted too high
-Audio amplifier not switching off
Radio Unmutes With No Carrier Present
When In Preset Condition
-Internal squelch trimmer adjusted improperly
-Open or shorted CAR PRES signal
Sensitivity Does Not Meet Specification
-Front-end filters misaligned or failing
-Software front-end tuning adjusted improperly
-RF preamplifier failing
-IF filter or amplifier failing
-VCO buffer failing
Receiver Distortion Out Of Specification -IF transformers mistuned
-Audio amplifier failing
Low or No Transmitter Audio Modulation -Transmit Analog or Digital Deviation misadjusted
-Microphone failing
-VCO modulation circuit failing
Summary of Contents for GPH-CMD
Page 1: ...GPH CMD PORTABLE RADIO Service Manual ...
Page 66: ...GPH CMD VHF Radio Maintenance BK RADIO Page 5 13 Figure 5 3 Receiver Test Setup ...
Page 103: ...GPH CMD VHF Radio Illustrated Parts List BK RADIO Figure 6 15 Front Cover Assembly Page 6 55 ...
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