Sony KV-27EXR15 drop out continues

[Darmok]

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.

 

[Art]

How about some of the caps and diodes on the input lines to the micro, from
the tac switches?

 

[Appreciate_It]

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.

Bill,
Have you tried this link? There are a lot of Sony (and others) TV
schematics in it. http://fileshare.eshop.bg/equipment_mfg/Sony_2.html
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 ! << Download

Just click on the "To download the file, please, click here ! " and
save the file. In some cases, you'll need to download more than 1
file, as the PDF file is broken down into several smaller parts.

I got this link from hanging out in this group - just paying it
forward - hope that someone else would benefit.

Appreciate_It.

 

[Darmok]

Bill,
Have you tried this link? There are a lot of Sony (and others) TV
schematics in it. http://fileshare.eshop.bg/equipment_mfg/Sony_2.html
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 ! << Download

Just click on the "To download the file, please, click here ! " and
save the file. In some cases, you'll need to download more than 1
file, as the PDF file is broken down into several smaller parts.

I got this link from hanging out in this group - just paying it
forward - hope that someone else would benefit.

Appreciate_It.

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

 

[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!

 

[RonKZ650]

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.

 

[Andy Cuffe]

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!

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

[email protected] <-- Use this address until 12/31/2005

[email protected] <-- Use this address after 12/31/2005

 

[Darmok]

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

[email protected] <-- Use this address until 12/31/2005

[email protected] <-- Use this address after 12/31/2005

Yep, both sound and picture just go out together .. like it was shut
off. However, its NOT off, as when I press the power button on the
front panel, I can hear the relay click into the OFF position. I wait
a minute, then press the button again, and it powers right up, and is
usually fine for the rest of the day .. or even days. Sometimes, the
even happens twice in a day, but usually only once. At no time is the
picture ever really bright. The picture, when the set is operating is
perfect .. not even overscanning.

Perplexed in Ohio ...

 

[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.

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

 

[kip]

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

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