Motorola ASTRO XTSTM 4000 Detailed Service Manual page 86

5-24
RX RF–Page 4
Clock
4
synthesizer
Measure
tuning voltage
(Vt) at R572
No
Fbit
< 1.2 MHz?
Yes
No
Vt= 3 Vdc?
Yes
Repair
defects
May 28, 2008
No
Vt = 0 Vdc?
Yes
5
Inspect clock
oscillator circuit at
U500-19, 20
Visual
No
examination
OK?
Yes
Replace
Varactor D570
5
Inspect
components
surrounding
U500
Visual
examination
5
OK?
Yes
Replace
Abacus
U500
Troubleshooting Charts: RX RF
No
Repair
defects
6871620L01-C