IC-761 drift/chirpy rx signals when tuner presets are adjusted

IC-761 drift/chirpy rx signals when tuner presets are adjusted

Post by asr.. » Wed, 05 Apr 2006 07:46:06

I have a strange problem with my IC-761 that I purchased recently.  Any
help would be great:

I notice that once in a while CW signals will start to sound a little
warbley, as if infected with a little AC hum.  At first I assumed this
was a characteristic of the TX signal on the other radio but soon
discovered that if I play with the auto-tune switch it will go away.
Further investigation has shown that if I have the tuner on and play
with the preset control it can start or stop the problem.  The issue
seems to be with interference to the rx signal from the auto tuner. Can
the auto tuner affect the synthesizer in this way?

Thanks,

Anthony

 
 
 

IC-761 drift/chirpy rx signals when tuner presets are adjusted

Post by Gary P. Fibe » Thu, 06 Apr 2006 10:33:26



Quote:>I have a strange problem with my IC-761 that I purchased recently.  Any
>help would be great:

>I notice that once in a while CW signals will start to sound a little
>warbley, as if infected with a little AC hum.  At first I assumed this
>was a characteristic of the TX signal on the other radio but soon
>discovered that if I play with the auto-tune switch it will go away.
>Further investigation has shown that if I have the tuner on and play
>with the preset control it can start or stop the problem.  The issue
>seems to be with interference to the rx signal from the auto tuner. Can
>the auto tuner affect the synthesizer in this way?

>Thanks,

>Anthony

Generally its the VCO trimmer caps causing that raspy signal. Usually
shows up on CW first. The tuner is not connected to the synthesizer at
all.

I think its coincidence the tuner makes the signal raspy, warbled

Gary K8IZ

 
 
 

IC-761 drift/chirpy rx signals when tuner presets are adjusted

Post by Robert Fanfan » Mon, 10 Apr 2006 05:41:19

My IC-765 had the same problem. I brought the radio to Icom & they fixed the
problem at no charge. I believe this is a known problem with the wax(?)
placed on top of the trimmer caps to hold them in place.

-rob




>>I have a strange problem with my IC-761 that I purchased recently.  Any
>>help would be great:

>>I notice that once in a while CW signals will start to sound a little
>>warbley, as if infected with a little AC hum.  At first I assumed this
>>was a characteristic of the TX signal on the other radio but soon
>>discovered that if I play with the auto-tune switch it will go away.
>>Further investigation has shown that if I have the tuner on and play
>>with the preset control it can start or stop the problem.  The issue
>>seems to be with interference to the rx signal from the auto tuner. Can
>>the auto tuner affect the synthesizer in this way?

>>Thanks,

>>Anthony

> Generally its the VCO trimmer caps causing that raspy signal. Usually
> shows up on CW first. The tuner is not connected to the synthesizer at
> all.

> I think its coincidence the tuner makes the signal raspy, warbled

> Gary K8IZ