Hello friends..

I was read few messages about bugs in IC-706. I guess that following text
help solve these bugs in most cases:

Most Common Failures and Cures for the Icom IC-706

Symptom:  Low RX sensitivity on 2-meters.
Probable Cause:  Burned D6 on PA unit.
Cure:  Replace D6 (MA862).

Symptom:  No TX power output on an HF band.
Probable Cause:  Bad filter relay.
Cure:  Locate and replace faulty filter relay (will be type
AHY-103).

Symptom:  Low/distorted RX audio.
Probable Cause:  Burned foil trace on PLL unit.
Cure:  Repair SPE (ground) foil trace on PLL unit.

Symptom:  Low TX output on HF & 6-meters.
Probable Cause:  Shorted D18 and Q1 in filter unit.
Cure:  Replace D18 (DAP222) and Q1 (2SC4081).

Symptom:  Inadequate mic gain.
Cure:  Install field mod on main unit:  Change value of
R236 from 27k, to 68k-82k. [The higher the resistor value,
the greater increase in mic gain.]

Symptom:  Thin-sounding mic audio.
Cure:  Install field mod inside HM-103:  Remove rubber
gasket from beneath mic element.

Symptom:  Off frequency in FM TX.
Probable Cause:  FM  VCO lock voltage needs adjustment.
Cure:  Adjust FM VCO lock voltage for 1.5 volts as per
service manual.

Symptom:  Unit is stuck in TX mode.
Probable Cause: Shorted T/R switch transistor.
Cure:  Replace shorted Q32 in main unit.

Symptom:  Radio won't power up.
Probable Cause:  Burned ground foil trace in flex cable.
Cure:  Replace flex cable EP2 at main board.