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Sony KV-27EXR15 drop out continues

Hi,

Had the set open to try a few things. Re-adjusted the G2 pot on the CRT board which cleared up the cold start flashes.

However, the sudden drop out of picture and sound continues to elude me. Whilst I had the unit open, I rapped on the various PC boards with the plastic end of a screw driver to try and locate a bad solder joint. No drop out. I also rapped on (what I believe was) the Horizontal cap on the "G" daughter board (side of case) without any results. No caps looked impaired ... bulging ... leaky .. whatever.

One thing I have noticed is, when it drops out, I CANNOT control the unit with the remote. I can, however, go up to the set and push the power button, and the relay inside responds. After leaving the power off for a couple minutes, I can turn the set on with either the button on the set, or the remote.

Looks like whatever is causing this is causing me to lose control via the remote .. but then, that returns too.

Schematics would help, but they no longer give those with sets. (this is marked manufactured in Aug. 1990)

When it is working, this is an outstanding TV, with great picture and sound. The annoying drop outs need to be diagnosed and fixed, however.

Thanks again.

Bill

PS .. there was 1/4" of dust inside the unit, which I vacuumed out. I also replace a yoke to tube rubber support wedge which had fallen down on the main board .. don't think that had anything to do with it.

Reply to
Darmok
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Reply to
Art

Bill, Have you tried this link? There are a lot of Sony (and others) TV schematics in it.

formatting link
If you know the chassis-type of your TV, you will find a similar schematic which will help a lot, even though it is not your exact model.

I noticed that they have a sony kv27exr95-anu2.rar and .r00. That may be almost exactly what you need. Download both files and unRar.

You should also download the "Sony TV TSS Logs.rar", which contains a lot of service info.

You do not need to register or anything. Select the file(s) you want, and click on it. On the following page, somewhere in the middle, you'll find a table:

Download restrictions information: Limit Downloaded Day 50 (some number) Month 500 (some number)

Download >> To download the file, please, click here !

Reply to
Appreciate_It

Thanks ... I'll give it a look!

Reply to
Darmok

Well, I downloaded a few of those files. I found a few references to "Shut Down" .. that is, the picture and sound going out at irregular intervals, and the ability to turn the set back on after it being off for a minute or so (but only from the front panel).

What I read wasn't good news. Seems the only "cure" is a new CRT! Bummer!

Reply to
Darmok

What the picture tube does when it's bad in certain Sony's is to be extremely slow initially getting a picture, sometimes 30 minutes or more and then the picture is on for a second or 2, then goes black for a second or 2, then back to picture over and over again. Sometimes there is no delay, just the on/off crap, but the common thing is on for a second or 2, off for a second or 2, over and over. I don't think this applies to your 1990 model, mostly 1993 and up had this problem. Very common problem is bad solder connections on the regulator transistors, which are mounted on metal brackets. I wouldn't condemn the set just yet.

Reply to
RonKZ650

If you're losing the picture and sound together, it's definitely not the CRT. A weak CRT will cause the picture to blink off, but the sound and all other functions will be fine. A shorted CRT could cause the set to shut down, but you would probably see a VERY bright picture first. Andy Cuffe

snipped-for-privacy@psu.edu

Reply to
Andy Cuffe

Reply to
Darmok

Well, this set definitely doesn't cycle on/off every 2 seconds. I just lose everything all of a sudden, but then can turn the set back on from the front panel .. or, if I wait long enough, even the remote will respond again. I did see the cycle issue listed in the Sony Troubleshooting Tips article.

The set used to blink several times upon cold power up, until the picture settle, but a small adjustment to the black G2 pot on the CRT board fixed that. So, the CRT may be a little weak, but not gone. Its got to be something else .. and intermittent failures are the most difficult to diagnose.

Bill

Reply to
Darmok

Why dont you take the TV to a repair shop and get an estimate as it certainly sounds like you dont have a clue as to what's going on. That's the intelligent way to go about it.

kip

Reply to
kip

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