User's Manual

Table Of Contents
6881094C31-C October 14, 2003
Troubleshooting Charts: RX RF 5-27
RX RF—Page 5
dac1 = dac2?
Measure prselector filter
tuning voltage dac1 and dac2.
VHF: None, TP29
UHF: TP401, TP405
700-800: TP401, TP405
No
Ye s
Is
unit
VHF?
No
Ye s
Replace IF filter.
VHF: FL451
UHF: FL490
700-800: FL403
Repair
defects
6
8
Visual
inspection
OK?
Remove IF filter shield. Check IF
filter and LC matching networks.
VHF: SH451
UHF: SH403
700-800: SH403
No
Ye s
VHF/UHF: Check discrete
preselector filters.
700-800: Replace FL401
or FL402.
Replace
PCIC
Dac
voltages
OK?
Tune the radio across several
channels. Measure dac2,
proportional to frequency.
No
Ye s
7
Replace
PCIC
MAEPF-27474-B
VHF
UHF
700-800
136
174
380
470
770
869
1.3
2.4
0.5
2.9
1.5
3.5
Band F (MHz) dac2 (Vdc)