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