This could be caused by a number of things. A short between the drivers and
the speakers could be bleeding current equally between the two. It could be
also on the input side. The switch itself could be shorting the two feeds
together. You'd need to open it up and test the signal path to find shorts.
Good luck if there're capacitors in the line...

--

____________________________________

Brandon Anderson
Lighting, Sound, and Video

http://www.bdanderson.com/


"Michael Salmons" wrote in message
om...
Hello,

I've gotten my hands on a very nice older Sony FM tuner (ST-A6B). It
has a few problems but the most troubling is it will only do mono, not
stereo. It has a mode switch with three positions: mono, hi-blend and
stereo. They are all identically mono EXCEPT in hi-blend, imagining it
as a stereo image, the sound is moved over a bit to the left, but
still with no channel separation.

This, as I stated before, is an older tuner, probably made in the
mid-seventies, all analog. Does this sound like the malfunction of a
certain part that I could replace? Could it be the MPX chip? Or maybe
the mode switch is bad?

Thanks,

Michael Salmons
salmonsm @ missouri . edu