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Sony TV KV-32XBR95S,horizontal light bands

My sony XBR is quite old (92 vintage) but still love the great picture. Recently it developed the problem of horizontal bands of light and dark across the entire screen which only appear in light scenes. If the picture is dark, there are no bands and the intensity or how visible the bands are is in direct proportion to how bright the picture is. It appears that the bands are a distortion in the vertical sync. Thought it could be a power supply related problem because of the sensitivity to brightness level. I do have the service manual for the TV. Any suggestions on where to start looking would be greatly appreciated.

Thanks in advance, Dan

Reply to
Dan
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Sounds like a classic case of jailbars, find the capacitor that filters the B+ to the video amp, usually it's a 250v lytic on the neck board but I haven't had that symptom on a Sony so it may be elsewhere.

Reply to
James Sweet

That Model is know for many bad filter caps and a mulitude of bad solder joints . A heavy weight set worth fixing.

kip

Reply to
kip

Kip Any suggestions on which filter caps are suspect in this case? Can I test them with a cap ESR meter that I have?

Reply to
Dan

May just be bad solder at the vertical IC. Sky.

Reply to
Skype_man

Reply to
Dan

Once a cap goes bad it stays bad? If a capacitor is marginal, in other words just barely outside of tolerance for ESR and in process of drying out, the temperature will affect how the capacitor acts in circuit. It is not uncommon for it to appear to work when it is warmed up when it is just outside of specification.

That being said, your specific symptom is more than likely solder connection related. The set will need carefully inspected for bad solder connections to all the low voltage regulators, the vertical ic, along with potential solder problems inside the tuner and IF can.

Reply to
dkuhajda

No, lytics heal sorta when the temp goes up. Many sets in the shop need a cooldown before we can see a symptom.

If you are indeed seeing rarifications in the scan lines head for the vertical, and if included, the N-S pincushion ckt or the dynamic convergence circuit. Of course you are still looking for electrolytics, most likely.

JURB

Reply to
ZZactly

Actually my symptoms only appear when temp goes up. Always start after set is on for some time and then may disappear after a time. Never appear when set is first turned on.

For the past 2 days, no symptoms, even after extended operation but I have not done anything to fix it.

Once again, thanks for all of your helpful responses. I'm a newbie on this list and it is the most responsive and helpful list I have ever posted to.

Reply to
Dan

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