Motorola pro7100 Servisní příručka stáhnout pdf (Strana 65)

Maintenance 3-11

3.9 VCO Troubleshooting Chart

LOW OR NO RF SIGNAL

AT TP4003

VISUAL CHECK

OF BOARD

OK?

4.5V DC AT

U4301 PIN 14&18

35mV DC AT

U4301 PIN 19

ARE Q4301

BASE AT 2.4V

EMITTER AT 1.7V

COLLECTOR AT 4.5V

CORRECT

PROBLEM

YES

MAKE SURE SYNTHESIZER IS

WORKING CORRECTLY AND

RUNNER BETWEEN U4201 PIN

28 AND U4301 PIN 14&18 IS OK.

CHECK RUNNER

BETWEEN U4201 PIN 2

AND U4301 PIN 19

REPLACE Q4301

IS RF AVAILABLE

AT BASE OF Q4332

IF ALL PARTS FROM U4301

PIN 8 TO BASE OF Q4332 ARE

OK, REPLACE U4301

ARE Q4332

BASE AT 0.7V

EMITTER AT 110mV

COLLECTOR AT 4.5V

IF ALL PARTS ASSOCIATED

WITH THE PINS ARE

OK, REPLACE Q4332

IF ALL PARTS FROM COLLECTOR

OF Q4332 TO TP4003 ARE

OK, REPLACE Q4332

YES

RX VCO

LOW OR NO RF SIGNAL

AT INPUT TO PA

VISUAL CHECK

OF BOARD

OK?

4.5V DC AT

U251 PIN 14&18

4.8V DC AT

U4301 PIN 19

ARE U251 PINS

13 AT 4.4V

15 AT 1.1V

10 AT 4.5V

16 AT 1.9V

IS RF AVAILABLE

AT TP4534

IF ALL PARTS ASSOCIATED

WITH THOSE PINS ARE

OK, REPLACE U4301

IF R4361 AND L4361 ARE

OK, REPLACE U4301

IF ALL PARTS FROM TP4534

YES

POWER OK BUT

NO MODULATION

AUDIO = 180 mVRMS

AT “-” SIDE OF

C4325

4.5VDC

AT CR4321

IF C4321 AND R4321

ARE OK, THEN

REPLACE CR4321

REPLACE

R4322

REPLACE C4325

YES

TX VCO

TO U4401 PIN 16 ARE OK,

REPLACE U4301

1 2 ... 60 61 62 63 64 65 66 67 68 69 70 ... 108 109

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