On Thu, 15 Sep 2005 14:49:33 -0400, "MTLnews"
wrote:
On another note, lucky me.... This morning, turn on my TV (SONY KV32S22) to
watch something before leaving for work, and all was fine for about 2
minutes, the picture goes black on the bottom 1/3rd of the screen. the top
2/3rds screen shows black on both sides coming down on a slight v-shape, and
horizontal black lines across the picture that is visible. Within about 30
secs, the screen will turn black, but sound was still there... Power off,
turn back on, and it is fine for about 30 secs, then same thing all over
again...Thought maybe the Video input I was using died, so tried with the
Tuner alone, and it did the same... Damn... I checked the service manual,
but there are way too many test points, and without much previous
experience, no way of easily narrowing it down... Not sure I'm ready or
patient enough to take the try to repair yourself path just yet...I hate to
replace the unit, since the image was very clear, and the unit is about 7
years old... But I don't want to spend $150 for someone to look at it, and
tell me it will cost me another $200 to repair... 
Anyone have any ideas on what it may be ?
Regards..
-Tony
I have a 15 year old 27" SONY that also had weird intermittent display
problems. A good slap on the cabinet would clear the problem for a
while. Since the image was sharp and clear when it was OK that meant
the components and circuitry were good. The slap fix meant that
there was a loose part, likely a cold solder, somewhere. The
diagnosis agreed with the observation as, when the furnace came on
causing thermal expansion, the problem appeared or, if already there,
disappeared.
I am knowledgeable in electronics and a little on TVs. Opened the TV
up several times but was unsuccessful in locating the problem because
I couldn't reproduce the problem. If I cannot reproduce the problem
then the TV repair guy would unlikely be able to do the same. I
didn't want the set sitting in the shop for months and I didn't like
their charges either. And who wants to tote around that hernia box.
Anyway after half a dozen tries over two years I got lucky. When my
elbow brushed against a wire harness the problem appeared. I could
jiggle the harness and consistently reproduce the problem. A close
inspection of the circuit board connector pins revealed lifted solder
pads from the donut holes. Iwould have never been able the cold
solder by just looking. Resoldered the pins and the TV worked fine.
The next time another intermittent problem appeared I went straight to
the jiggle test for all the wire harnessess. Use long wood rod so
that you don't accidently get zapped. Being zapped is unpleasant but
I have never come across any report of anyone having died. I quickly
located the problem and it was again connector pins with lifted solder
pads. Resoldered the connector and the image is now even sharper and
clearer than it had ever been.
I had earlier posted my problem to the sci.electronics.repair NG and
had terribly technical suggestions which were non starters. This was
because the layout ot the PCB and the rest of the TV modules were so
compact that it was impossible to stick even a simple multimeter probe
to measure anything. And everything had to be insitu because the
harness wires were not long enough to relocate the PCB to a more
accessible place. After I posted my solution someone replied that
SONY PCBs are wellknown for developing cold solder joints. Aha.
Its next to impossible your trying to repair any circuitry components
yourself. If you want to have a go at fixing the TV yourself do the
jiggle test. Nothing technical and no parts required. Cold solder
joints are very easy to fix if you can find them. Else live with it
or junk it. As consumer electronics products stand these days it is
not worth shop repairs either. For what a service shop charges you
might as well use that money towards the price of a new TV set.