Motorola ASTRO XTS 5000 - Page 128

6881094C31-E November 16, 2006
Troubleshooting Charts: TX RF (VHF and UHF Range 2) 5-37
TX RF (VHF and UHF Range 2)—Page 2
MAEPF-27420-C
RAWB+
about
7.2 Vdc?
Measure
RAWB+
at Q107-drain
No
No
No
Yes
Yes
Yes
Check
continuity
V.gate
about 2 to
3 Vdc?
Check
continuity
DC bias is OK,
control is OK,
RFIN is OK,
PA has low gain
Replace
Q107
No
Yes
Measure RF
level at
pin 6 of Q107
Is unit
VHF or
UHF R2?
No
Yes
Remove SH10
1
and check for
parts off pad
Level
about
+35 dBm?
Replace U102. For VHF and
UHF Range 2, check under
SH101. if all parts soldered,
replace U102.
Measure gate bias
at L108 for VHF and
L720 for UHF Range 2
RAWB+
about
7.2 Vdc?
Measure
RAWB+
at U102-6
No
No
Yes
Yes
TX7V
about
7.2 Vdc?
Check
continuity
Measure
Vgate at TP111,
normally 4 to
5.5 Vdc
Measure
TX7V at
U102-14
DC bias is OK,
control is OK,
RFIN is OK, driver
has low gain
Vgate
> 4 Vdc?
2
1
3
4