I rescued a stereo decoder from a GE B/W TV stereo combo that was out
for trash collection. I don't know what model it was because the back
was missing, but the tubes are all 1961 date codes. That would make it
about as early as it gets for FM stereo. The fact that they would put a
completely self contained decoder with RCA jacks and a cheater cord
power connector in a console also dates it.

After repairing a break in the primary winding of the power transformer
and replacing the selenium rect and filter caps it seems to work with my
Heathkit AJ-30, but clearly needs a serious alignment.

It uses a 12AX7 and 12AT7, has 4 adjustable coils, one adjustable
transformer and a pot. I was able to get some separation by adjusting
the pot, which I assume adjusts the ratio of L-R to L+R that goes into
the matrix. Unfortunately, this adjustment had the effect of reducing
the overall output to very low level and the L and R channels seem to be
out of phase. Does anyone know where I could find a schematic and/or
alignment instructions of this, or a similar decoder? It's probably
covered in sams, but I don't have many from the early 60's. The only ID
on the decoder is 'A-42' stamped on it. I'd rather not try to align it
blindly. It's bad enough even with instructions.
--
Andy Cuffe