[ICOM] Bad TX audio on 775

[Greg Mijal]

Before anything else, I suggest you make sure that the distortion is not rf 
gettng into the audio.  A 200 uh choke in line with the mic audio helps alot 
in this situation.
Greg
WA7LYO
in sunny Feenix
----- Original Message ----- 
From: "Igor Sokolov" <ua9cdc at r66.ru>
To: "ICOM Reflector" <icom at mailman.qth.net>
Sent: Saturday, October 14, 2006 12:39 PM
Subject: Re: [ICOM] Bad TX audio on 775


> The mike is the Heil  Proset for Icoms head set. I do not think 
> overdriving
> is the reason. The distortions especially obvious when speaking into the
> mike in low voice. 3 or 4 different microphones were tried. I start to
> suspect it might be not the chip but some of the electrolytic capacitors
> associated with the chip.
>
> 73, Igor UA9CDC
>
>
>> Are you using an "amplified" microphone? - If so it could be overdriving
> the
>> input.
>>
>>
>> ----- Original Message -----
>> From: "Igor Sokolov" <ua9cdc at r66.ru>
>> To: "ICOM Reflector" <icom at mailman.qth.net>
>> Sent: Saturday, October 14, 2006 6:01 AM
>> Subject: [ICOM] Bad TX audio on 775
>>
>>
>> > Posting this for a friend:
>> > His 775 got some distorted audio on TX. Careful tracing led  him to
>> > suspect
>> > IC8 M5282FP audio amp.
>> > Service manual says pin 2 of the IC should be at 3.8V while in practice
> it
>> > is only 2.6V.
>> > Does anybody know where  I can get data sheet on the IC?  Where one can
>> > get
>> > this IC from? Do you thing it is the IC or  rather some parts
> (resistors,
>> > capacitors) associated with this IC?
>> > Any help would be appreciated.
>> >
>> > 73, Igor UA9CDC
>> >
>> > ----
>> > Your Moderator: Dick Flanagan K7VC, icom-owner at mailman.qth.net
>> > Icom Users Net: Sundays, 1700Z, 14.316 MHz
>> > Icom FAQ: http://www.qsl.net/icom/
>>
>> ----
>> Your Moderator: Dick Flanagan K7VC, icom-owner at mailman.qth.net
>> Icom Users Net: Sundays, 1700Z, 14.316 MHz
>> Icom FAQ: http://www.qsl.net/icom/
>
> ----
> Your Moderator: Dick Flanagan K7VC, icom-owner at mailman.qth.net
> Icom Users Net: Sundays, 1700Z, 14.316 MHz
> Icom FAQ: http://www.qsl.net/icom/