May 28, 2008
6871620L01-C
5-28
Troubleshooting Charts:
TX RF
TX RF–Page 3
INT > 5 Vdc?
Vgate at TP111
is low (< 4 Vdc)
Measure INT
at TP104
Yes
No
No
Yes
Yes
No
Replace
Q101
INT is low.
Measure VLIM at
PCIC U104 pin 19
PCIC is
programmed.
Measure TEMP
at R135
Bad PCIC
Replace U104
VLIM
about 2 to
3 Vdc?
No
Yes
Measure
RFIN at
C128
TEMP
< 1.0 Vdc at
25C?
RFIN is low, INT
is low, bad PCIC,
replace U104
< 0.5 Vdc?
Low output power,
RFIN is high, check
Secoondary Cutback
circuit (Q102,
RT150,
R120, R121, R122).
Repair defects.
Repair temperature
sensor circuit
(U103 & R135)
3
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: ......