[ICOM] IC-765 transmit audio problem

[Jack/W6NF]

Mike Olbrisch wrote:
> Don't know about the 765, but earlier (740-745) had a problem with the
> compressor switch.  Symptoms were much as you describe.  Replacing it would
> restore full output.  Cleaners didn't cut it, only replacing the switch was a
> permanent fix.
>
> Hope that helps.
>
> Mike - KD9KC.
> El Paso, Tx.
> DM61rt
>   
Hi, Mike:

Doesn't seem to be the compressor switch but I will check that further. 
Someone did send me a link to ICOM that had this information and, 
although I did not have any indications of raspy/distorted audio, this 
symptom fits my situation exactly:

>
>       Knowledge Base Article 5BBA592A68
>
> Issue
> Distorted/raspy-sounding TX in SSB modes on my 765. Average power is 
> low, even at higher mic gain levels. Turning on the speech processor 
> seems to help a little. CW, RTTY and FM seems normal.
>
> Resolution
> No bias voltage to driver or PA transistors. Measure voltages at bases 
> of driver and PA transistors in TX SSB mode. Should be around .67 
> volts. 0 volts indicates trouble.
>
> To fix:
> Replace bad Q6 transistor (2SD880Y) on PA unit. If problem is 
> intermittent, check for bad solder at the legs of Q6 transistor, or D2 
> diode.
>
> Category
> Amateur : HF : 765
>

Thanks for the suggestion!

73,

Jack, W6NF