Motorola ASTRO XTS 5000 Detailed Service Manual page 129

5-38
TX RF (VHF and UHF Range 2)—Page 3
3
TX7V is low.
Measure TXINH
at P1-19, Q101-b
TXINH
< 1 Vdc?
Yes
Measure RXH
at U104-23
and Q103-b
RXH
< 1 Vdc?
Yes
RXH
> 5 Vdc?
Yes
Trace dc levels
through switching
transistors Q101,
Q102, Q103,
and Q106
Replace bad
transistors
November 16, 2006
Bad control
No
signal from
VOCON
No
4
No
Bad PCIC
Replace U104
Troubleshooting Charts: TX RF (VHF and UHF Range 2)
4
Vgate at TP111
is low (< 4 Vdc)
Measure INT
at TP104
Yes
INT > 5 Vdc?
No
INT is low.
Measure VLIM
at TP119
VLIM
No
about 2 to
3 Vdc?
Yes
PCIC is
programmed.
Measure TEMP
at R124
TEMP
No
< 1.0 Vdc at
25C?
Yes
Measure
RFIN at
TP101
TP101 No
< 0.5 Vdc?
Yes
RFIN is low, INT
is low, bad PCIC,
replace U104
Replace
Q108
Bad PCIC
Replace U104
Repair temperature
sensor circuit
(U103, Q109,
R130)
Low output power,
RFIN is high, check
RF detectors and
op amp U106.
Repair defects
MAEPF-27476-A
6881094C31-E