6881094C31-E November 16, 2006
Troubleshooting Charts: RX RF 5-35
RX RF—Page 5
dac1 = dac2?
Measure prselector filter
tuning voltage dac1 and dac2.
VHF & UHF2: None, TP29
UHF R1: TP401, TP405
700-800: TP401, TP405
No
Yes
Is unit
VHF or UHF2?
No
Yes
Replace IF filter.
VHF & UHF2: FL451
UHF R1: FL490
700-800: FL403
Repair
defects
6
8
Visual
inspection
OK?
Remove IF filter shield. Check IF
filter and LC matching networks.
VHF & UHF2: SH451
UHF R1: SH403
700-800: SH403
No
Yes
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
Yes
7
Replace
PCIC
MAEPF-27474-C
VHF
UHF R1
UHF R2
700-800
136
174
380
470
450
520
770
869
1.3
2.4
0.5
2.9
1.2
3.6
1.5
3.5
Band F (MHz) dac2 (Vdc)
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