Vco Troubleshooting Chart (200 Mhz) - Motorola CDM1550 LS+ Detailed Service Manual

Maintenance
3.12 VCO Troubleshooting Chart (200 MHz)
RXVCO
TXVCO
LOW OR NO RF SIGNAL
ATTP3001
LOW OR NO RF SIGNAL
POWER OK BUT
NO MODULATION
NO
MAKE SURE SYNTHESIZER IS
WORKING CORRECTLY AND
RUNNER BETWEEN U3301 PIN -Ioiii~.:..::::<:::_
28 AND U4301 PIN 14&18 IS OK.
CHECK RUNNER
">-----~BETWEEN
U3201 PIN 2..,..1----<
AND U3301 PIN 19
REPLACE 03301
>..;,_---~AND/OR Q3302
IF ALL PARTS FROM U3301
~-~PIN
8 TO BASE OF Q3301 ARE
OK, REPLACE U3301
TROUBLESHOOT 03301
~~~ CIRCUITRY
TROUBLESHOOT RX INJECTION
FILTER.
TROUBLESHOOT
TRANSMITIER
IF ALL PARTS ASSOCI-
~~--~
ATED WITH THOSE PINS
TROUBLESHOOT
.>~~ AUDIO CIRCUITRY
ARE OK, REPLACE U3301
IF L3331, C3315, L3317,
R3401-3 ARE OK,
>----~
REPLACE U3301
3-15