Have a Zenith Model SM3583BT 35" TV with gray and distorted video.
Determined that the tv had a
defective IF Block (Part # 9-1320). After replacing the block, the video
was restored. However
a new problem was encountered. All stations were received as mono with
the left speaker
inoperative. The audio amp (IC810 TA8218AH) was resoldered from a
previous repair. The amp proved
to be ok since the audio signal for the left channel was not even being
received at the input
of the amp. As a result, I replaced the Sony MTS ic (IC 1400 CXA1264AS)
and the corresponding
quad amp (IC 1404 221-129). The problem still persists. In the service
menu, I enabled Dolby
which was not active. On the user's menu, I attempted to enable SEQ in
the audio menu but was
informed by the OSD that the station was not in stereo, which I knew was
false. For only one
attempt out of many was I able to enable SEQ which allowed the left
channel to operate. Looking
at the pinout of the IF Block, I was able to identify the IF, AGC, test,
and Audio Output pins
on the four pin plug. However, the three pin plug part of the IF Block
is more difficult. I
believe that two of the pins are Vcc and Video output. However the third
pin is traced to IC6000
which is the microcontroller. Is it possible that this is a stereo
detect signal or is that
signal carried on the data line? Has anyone encountered such a problem?
Thanks ahead for any
tips, Ron.


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