May 28, 2008
6871620L01-C
5-24
Troubleshooting Charts:
RX RF
RX RF–Page 4
Yes
Fbit
< 1.2 MHz?
Measure
tuning voltage
(Vt) at R572
No
No
No
Yes
Yes
Vt= 3 Vdc?
Repair
defects
Replace
Varactor D570
Replace
Abacus
U500
Repair
defects
Visual
examination
OK?
4
Visual
examination
OK?
Inspect
components
surrounding
U500
No
Yes
5
5
No
Yes
Inspect clock
oscillator circuit at
U500-19, 20
Vt = 0 Vdc?
5
Clock
synthesizer
Summary of Contents for ASTRO XTSTM 4000
Page 1: ...COLOR CHORDS 7 ASTRO XTSTM 4000 Portable Radio Detailed Service Manual ...
Page 2: ......
Page 16: ...May 28 2008 6871620L01 C xiv Commercial Warranty Notes ...
Page 22: ...May 28 2008 6871620L01 C 1 6 Introduction Notes ...
Page 26: ...May 28 2008 6871620L01 C 2 4 Radio Power Notes ...
Page 56: ...May 28 2008 6871620L01 C 3 30 Theory of Operation Notes ...
Page 100: ...May 28 2008 6871620L01 C 6 8 Troubleshooting Waveforms Notes ...
Page 194: ...May 28 2008 6871620L01 C B 2 Motorola Service Centers Notes ...
Page 204: ...May 28 2008 6871620L01 C Glossary 10 Glossary Notes ...
Page 209: ......