I have a Sony KV-35S40 that will resurrect after replacing HOT, PS
driver and 0.1 ohm fusable resistor. It plays beautifully for about a
week, 3 or 4 movies, then blows. My friend saw it go, said the
horizontal width shrank to about 80-90% over a few seconds, then poof.
Any ideas?

Presume that he did not and therefore the assumption of his failure??
"dkuhajda" wrote in message
...
Can we assume you used all Sony OEM parts?
Can we assume you removed the horizontal driver transformer and cleaned
the
connections and resoldered them?

David

diff wrote in news:0xQXc.175482$Oi.77495@fed1read04:

I have a Sony KV-35S40 that will resurrect after replacing HOT, PS
driver and 0.1 ohm fusable resistor. It plays beautifully for about a
week, 3 or 4 movies, then blows. My friend saw it go, said the
horizontal width shrank to about 80-90% over a few seconds, then poof.
Any ideas?

Can we assume you used all Sony OEM parts?
Can we assume you removed the horizontal driver transformer and cleaned the
connections and resoldered them?

David

diff wrote in news:0xQXc.175482$Oi.77495@fed1read04:

I have a Sony KV-35S40 that will resurrect after replacing HOT, PS
driver and 0.1 ohm fusable resistor. It plays beautifully for about a
week, 3 or 4 movies, then blows. My friend saw it go, said the
horizontal width shrank to about 80-90% over a few seconds, then poof.
Any ideas?

I used 2SC5148, MX0841, (Original part #'s) and OEM Sony fuse res.

I did not remove the flyback, but did micro-vacuum both boards, esp
around the flyback.

I did inspect all solder joints under Bausch&Lomb stereoscope around the
HOT and flyback.

I did not check the HOT temperature after it had run for a while. I was
lazy or thought the job was done. I have an IR probe, so it's something
to check. (I don't fancy sticking my finger in there ;-)

With this additional info, any hypotheses?

-diff

dkuhajda wrote:
Can we assume you used all Sony OEM parts?
Can we assume you removed the horizontal driver transformer and cleaned the
connections and resoldered them?

David

diff wrote in news:0xQXc.175482$Oi.77495@fed1read04:


I have a Sony KV-35S40 that will resurrect after replacing HOT, PS
driver and 0.1 ohm fusable resistor. It plays beautifully for about a
week, 3 or 4 movies, then blows. My friend saw it go, said the
horizontal width shrank to about 80-90% over a few seconds, then poof.
Any ideas?

Going by your description, the horizontal driver transformer, NOT the
flyback may be the fault. It sometimes goes cold soldered or defective in
these sets. I have had to change them on occasion. This is the transformer
that is driving the HOT. The scan generator feeds a transistor that drives
this transformer. The transformer drives the HOT. The HOT drives the
flyback. On rare occasions I have also seen the flyback cause this type of
failure. In your model, it should be located towards the front of the
chassis on the right side (going from memory). It looks like a small back
colored transformer, that is about 1 to 1.5 inch across in size.

If the HOT looses the drive pulses while operating, it will fail. When it
fails, it is also possible that it will blow a number of parts in the power
supply. If it did not damage the power supply on these occasions, you are
very lucky.

It is strongly suggested to use Sony original parts only. If not, they most
likely will not last very long.

--

Jerry G.
==========================


"diff" wrote in message
news:0xQXc.175482$Oi.77495@fed1read04...
I have a Sony KV-35S40 that will resurrect after replacing HOT, PS
driver and 0.1 ohm fusable resistor. It plays beautifully for about a
week, 3 or 4 movies, then blows. My friend saw it go, said the
horizontal width shrank to about 80-90% over a few seconds, then poof.
Any ideas?

Ditto, my vote is on the horizontal driver transformer solder connections,
fairly common.

Second vote would be an intermittent short in the crt, also somewhat common
on the 32" sony but less common on the 35" tube. The shutdown circuitry
usually will shutdown the tv before the overcurrent takes out the HOT 99%
of the time however.

David


"Jerry G." wrote in
:

Going by your description, the horizontal driver transformer, NOT the
flyback may be the fault. It sometimes goes cold soldered or defective
in these sets. I have had to change them on occasion. This is the
transformer that is driving the HOT. The scan generator feeds a
transistor that drives this transformer. The transformer drives the
HOT. The HOT drives the flyback. On rare occasions I have also seen
the flyback cause this type of failure. In your model, it should be
located towards the front of the chassis on the right side (going from
memory). It looks like a small back colored transformer, that is about
1 to 1.5 inch across in size.

If the HOT looses the drive pulses while operating, it will fail. When
it fails, it is also possible that it will blow a number of parts in
the power supply. If it did not damage the power supply on these
occasions, you are very lucky.

It is strongly suggested to use Sony original parts only. If not, they
most likely will not last very long.

Did the 2SC5148 come sealed up in a Sony bag?
Did it come from Sony spare parts if it was not in a sealed bag.

Some campanys how sell TV parts might have 2 lots of transistors one the
real on at twice the price and a cheaper version that's only good for a
short time.



"diff" wrote in message
news:OHWXc.180146$Oi.10784@fed1read04...
I used 2SC5148, MX0841, (Original part #'s) and OEM Sony fuse res.

I did not remove the flyback, but did micro-vacuum both boards, esp
around the flyback.

I did inspect all solder joints under Bausch&Lomb stereoscope around the
HOT and flyback.

I did not check the HOT temperature after it had run for a while. I was
lazy or thought the job was done. I have an IR probe, so it's something
to check. (I don't fancy sticking my finger in there ;-)

With this additional info, any hypotheses?

-diff

dkuhajda wrote:
Can we assume you used all Sony OEM parts?
Can we assume you removed the horizontal driver transformer and cleaned
the
connections and resoldered them?

David

diff wrote in news:0xQXc.175482$Oi.77495@fed1read04:


I have a Sony KV-35S40 that will resurrect after replacing HOT, PS
driver and 0.1 ohm fusable resistor. It plays beautifully for about a
week, 3 or 4 movies, then blows. My friend saw it go, said the
horizontal width shrank to about 80-90% over a few seconds, then poof.
Any ideas?





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"diff" wrote in message
news:0xQXc.175482$Oi.77495@fed1read04...
I have a Sony KV-35S40 that will resurrect after replacing HOT, PS
driver and 0.1 ohm fusable resistor. It plays beautifully for about a
week, 3 or 4 movies, then blows. My friend saw it go, said the
horizontal width shrank to about 80-90% over a few seconds, then poof.
Any ideas?

Bad connection (cracked solder joint) to the driver transformer of the horiz
output transistor. Common problem