Motorola ASTRO XTS 5000 Detailed Service Manual page 73

Troubleshooting Charts: TX RF (UHF R1/700-800 MHz)
TX RF (UHF R1/700-800 MHz)—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
6881094C31-C
Bad control
No
signal from
VOCON
No
4
No Bad PCIC
Replace U104
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 R130
Repair temperature
TEMP
No
< 1.0 Vdc at
25C?
Yes
Measure
RFIN at
TP101
Low output power,
RFIN is high, check
TP101
No
RF detectors and
< 0.5 Vdc?
Yes
RFIN is low, INT
is low, bad PCIC,
replace U104
5-33
Replace
Q108
Bad PCIC
Replace U104
sensor circuit
(U103, Q109,
R130)
op amp U106.
Repair defects
MAEPF-27476-O
October 14, 2003