Icom IC-735 Common Questions page 2

feedback.
If nothing helps, radio should be checked for spurious output. (see
Remarks:
below)
Spurious TX on some bands. SWR reading may be high when
Symptom:
transmitting into a dummy load. Power is low on some bands. Ic may
be high.
Probable
Bad components on PA unit caused by over-voltage or overheating.
Cause:
Check and replace as needed: C25 & C29 (1000uF, 16v) and R25
Cure:
(4.7 ohm, 2 watt) on PA unit. Also look for overheated components
and solder joints on the L4 assembly.
Power drops off as unit warms up. ALC meter deflection remains
Symptom:
high.
Probable
APC out of alignment.
Cause:
Follow APC alignment procedures in the service manual. (R262 on
Cure:
main unit.)
Distorted RX/TX, or no RX/TX on one or more bands. Distorted SSB
Symptom:
audio sounds raspy and rough. Problem may be temperature related.
Probable
Bad trimmer capacitors on PL unit, HPL VCO section.
Causes:
Replace plastic trimmer capacitors C37, C45, C52, and C59 with
Cure:
ceramic equivalents. Also replace the reference oscillator trimmer
C138.
Frequency instability.
Symptom:
Probable
Unstable plastic trimmer capacitor C138 on PL unit.
Causes:
Replace C138 with a ceramic equivalent. We also recommend
Cure:
replacing the HPL trimmers at this time.
Intermittent mic audio.
Symptom:
Probable
Dirty mic gain control.
Causes:
Spray-clean control with
Cure:
Using a cleaning solvent other than
Remarks:
by removing a substance inside the control that allows smooth
movement of the slider.
VFO tuning is erratic, sometimes lags or skips when changing
Symptom:
frequencies or bands. Sometimes least-significant digit in frequency
displays "flutters" back and forth instead of changing incrementally
when the VFO knob is turned slowly.
solvent.
Blue Showers
Blue Showers
may cause damage