Icom IC-761

problem, then most likely either the drivers or PA transistors are bad,
especially if the ALC meter deflection is low.
Remarks: Spurious output may be caused by incorrect band switch voltage to
the low-pass filter unit, or even faulty/burned components on the
filter unit itself. The above causes should be ruled out first, however,
since low-pass filter failures are uncommon in the IC-761.
Symptom: Radio seems to be stuck in "scan" mode.
Probable
Cause:
Bad IC2 on the logic unit.
Cure: Replace IC2 (RP5G01-007)
Symptom: Intermittent display. S-meter may peg and RX/TX may disappear
when the unit is in the failure mode.
Probable
Cause:
Cracked solder beneath the DP-6 DC-DC converter IC (IC1) on the
display unit.
Cure: Carefully remove the DP-6 converter IC from the display unit and
resolder the pins of the IC to its circuit board. Then reinstall the
DP-6 back on the display unit.
Symptom: VFO tuning is erratic, sometimes skips frequencies in a certain area
if VFO knob travel. Least significant digit in frequency display
sometimes "flutters" back and forth instead of changing
incrementally when the VFO knob is turned slowly.
Probable
Cause:
Bad rotary encoder.
Cure: Substitute rotary encoder with a known good one. It is recommended
that the rotary encoder be replaced as a complete assembly if it is
bad.
Remarks: If the unit tunes in only one direction, i.e. either up or down, there
may be a problem on the logic unit.
Symptom: Loud, high pitched squeal emanates from inside radio. May be
intermittent.
Probable
Cause:
DC-DC converter transformer has a loose core.
Cure: Replace DP-6 on the display unit.
Symptom: A whine emanates from inside radio in TX only at certain power
levels. Transmitter works ok.
Probable
Cause:
Loose core in DC-DC converter transformer inside power supply.
Cure: Replace T2 on reg. unit inside power supply.