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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SAP mode is turned on in the user menu. There may be corrupted data in the
eeprom causing improper operation of the if block. You did perform the
alignments in the service menu after replacing the IF block as required per
the service manual, didn't you? You may simply be chasing a problem that is
a result of not completing the initial repairs.

David

"Ron Novini" wrote in message
news:6d2c777e7ac590ce414fb1524468eba3.123933@mygat e.mailgate.org...
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.


--
Posted via Mailgate.ORG Server - http://www.Mailgate.ORG