6871620L01-C
May 28, 2008
Troubleshooting Charts:
TX RF
5-27
TX RF–Page 2
RAWB+
about
7.2 Vdc?
Measure
RAWB+
at Q107-drain
No
No
No
Yes
Yes
Yes
Check
continuity
V.gate
VHF:
about 3 to
4 Vdc?
UHF:
3 Vdc?
Check
continuity
DC bias is OK,
control is OK,
RFIN is OK,
PA has low gain
Replace
Q107
Measure RF
level at
pin 6 of Q107
No
Yes
Remove SH08
and check for
parts off pad
Level
about
+35 dBm?
Check parts under SH06.
If all parts are OK,
replace U102.
Measure gate bias
at C127
7.2 Vdc?
Measure
DC Level
at U102-6
No
No
Yes
Yes
7.2 Vdc?
Check
continuity
Check
continuity
Measure
Vgate at TP111,
normally 4 to
5 Vdc
Measure
DC Level at
U102-14
DC bias is OK,
control is OK,
RFIN is OK, driver
has low gain
Vgate
> 4 Vdc?
2
1
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: ......