vintage sony fm tuner- no stereo, only mono!

Archived from groups: rec.audio.tech (More info?)

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