This modification brings up the gain of the first mic-amp to the same level on the IC-775 as on the IC-756. I use the Heil Pro-set Plus with HC-4 and HC-5 combination. After modification the mic-gain is set to 11 o clock, drive to 12 o clock with COMP on. Without compression I increase mic-gain to 12 to 1 o clock. As the first mic-amp is located before the VOX circuit also the VOX start to work with the dynamic Heil elements after modification.
The modification involves taking the whole front unit of the radio as the mic-amp is located on MAIN UNIT. The resistor that is changed is a 2mm long (short) SMD resistor and is close to other components. I think it is best to consult the service manual to find out how to get to the MAIN UNIT and to find the resistor. Do not do this modification unless you know what you are doing and know how to solder SMD components. The IC-775 is a fine radio. Do not destroy it.
To do the modification, remove the 4,7k resistor R32 and exchange it with a 10k. R32 is connected between pin 3 and 4 on IC-8 on the MAIN UNIT.
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