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David
 
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Default Sony 53XBR35 Pincushion/convergence problem

One special note. When you remove the old convergence ic's, completely
remove the old heatsink compound and reapply an air tight thin coating of
heatsink compound to the new ic's. Make sure they are firmly attached to
the heatsinks.

Be very careful not to damage or overheat the circuit boards when removing
the old parts. Sony boards tend to be easily damaged and lift the circuit
traces.

David

Mirek Chmiel wrote in message
news:3fb80cf5$0$9745$afc38c87@...
This TV is about 7 years old. About 2 years ago it had similar problem. At
that time, we had a local company fix it. On the bill, they stated
replacement of one transistor. Unfortunately, I don't have that info

anymore
to specify which one.
This time, I did google search on this problem and found much useful info.
The purpose for this email is to further pinpoint the root cause of my
problem.
For a couple of weeks, while TV was warming up, I did notice short picture
problems. For a fraction of a second the picture would be distorted.

Because
of a short duration, I couldn't tell exactly what the distortion was.
Yesterday my family told me, that there was a problem with TV. I couldn't
immediately check it out so can't say, if this was instantaneous or not.
When I finally looked at it, I saw a pincushion problem. Today I replaced
F902 fuse and for a short while, everything is OK. After few seconds

(10-20)
the red color fails and, on the convergence screen, it moves off half of

the
screen to the left. Blue is still pretty good. At this time, I can smell a
burning component and I turn the TV off. After checking for hot

components,
I did notice, that the top STK is hot.

At this time, I'll follow the advice from David Kuhajda from 2000/06/09

for
a Sony RPTV KP-41EXR96 :
If the fuse is blowing, even intermittently you need to Replace both STK
convergence output ic's, check all the low ohm resistors in the

convergence
output circuit. Then check the vertical output ic and the 2 small fusible
resistor to the vertical ic, typically when one of the convergence ic's
starts
to go it opens up the fuse, which unbalances the voltage to the vertical

ic,
if
it is not bad now, it will likely fail within the next month. I had 3 in

a
row
that got 2 convergence ic's and a fuse, only to have the vertical ic fail
within
a month later, so we now replace the vertical ic whenever either the +15v

or
-15v fuse opens up, order the ic by number from MCM or other generic parts
distributor, as well as the stk outputs, Sony wants way too much for these
high
volume parts, and they buy them from the other manufacture as well.
David

If anyone has any additional info/advice please let me know.

Thank you.

Mirek