On Fri, 30 Jun 2017 09:04:44 -0500, Chuck wrote:

On Fri, 30 Jun 2017 08:44:00 -0500, Chuck wrote:

On Thu, 29 Jun 2017 14:02:39 -0700 (PDT),
wrote:

Back in February or March of 2010 the TV began changing from any channel to channel 2 intermittently. Sometimes very frequent. Other times more intermittent but it would not go more than a few hours without the problem popping up. Replaced IC0102 (MN14834HH) Main IC for the Channel Selection Ckt but no help. Remote control IR circuit not the problem as I disabled it. Over time have replaced some bad unrelated hw (burnt resistor, Caps). Have schematics and service manual but can't isolate the problem. Nice picture and everything else works fine. Unit in storage but every 4 months or so, when I see it and think about it, I fire it up. Hate to trash this old tv. Kind of part of the family now. Has anyone ever heard of this before?
I ran the television service department in the corporate headquarters
for the largest seller of Hitachi sets at that time in the U.S. so I
might be able to help you. First disconnect pin 17 and 18 of IC0102
and see if the problem disappears. If so, then it is likely the
channel tact switches. If not, take freeze spray and a hair dryer to
the tuner. The two main failures in this model, when there were tuner
problems, were the ic you replaced and the tuner itself. The band
switch IC IC0104 occasionally would fail and any 2SC458s in the
circuitry can cause problems. If these checks don't work, post again
and we'll go deeper in depth. Chuck

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Also replace C703 and R703 (off the flyback) if the previous hints
don't work.
Ignore my last post; I followed a wire incorrectly. These parts are
in the XRay shutdown circuit and do not pertain to your problem.