Just had a Sony Model KV-1380R given to me a couple of days ago. Only
problem is simultaneous but intermittent horizontal and vertical
shrinkage of about 20%, on a random basis. Removed the set back,
problem is still intermittent, but appears to be less frequent. Tried
beating on anything related to power supply, both in normal and
trouble modes, no effects. I suspect something in the power supply
since both H & V are affected. Currently running the set with a
voltmeter on B+ which is running about 155V, waiting for something to
go wrong. But I can't sit around watching the set, just check it
intermittently. Anyone had similar problems with this or similar
Sonys. Photofact folder is 2564, putting manufacture date at sometime
in 1987 or early 1988. If anyone has a pdf of this folder, please let
me know.

"hr(bob)

Just had a Sony Model KV-1380R given to me a couple of days ago. Only
problem is simultaneous but intermittent horizontal and vertical
shrinkage of about 20%, on a random basis. Removed the set back,
problem is still intermittent, but appears to be less frequent. Tried
beating on anything related to power supply, both in normal and
trouble modes, no effects. I suspect something in the power supply
since both H & V are affected. Currently running the set with a
voltmeter on B+ which is running about 155V, waiting for something to
go wrong. But I can't sit around watching the set, just check it
intermittently. Anyone had similar problems with this or similar
Sonys.


** Might be an idea to change any caps, varistors etc connected to the yoke.

An intermittent short in one could affect the pic size like you say.


...... Phil

hr(bob) wrote:
Just had a Sony Model KV-1380R given to me a couple of days ago. Only
problem is simultaneous but intermittent horizontal and vertical
shrinkage of about 20%, on a random basis. Removed the set back,
problem is still intermittent, but appears to be less frequent. Tried
beating on anything related to power supply, both in normal and
trouble modes, no effects. I suspect something in the power supply
since both H & V are affected. Currently running the set with a
voltmeter on B+ which is running about 155V, waiting for something to
go wrong. But I can't sit around watching the set, just check it
intermittently. Anyone had similar problems with this or similar
Sonys. Photofact folder is 2564, putting manufacture date at sometime
in 1987 or early 1988. If anyone has a pdf of this folder, please let
me know.

Does the picture brightness remain the same?

Sylvia.

"hr(bob) " wrote in message
...
Just had a Sony Model KV-1380R given to me a couple of days ago. Only
problem is simultaneous but intermittent horizontal and vertical
shrinkage of about 20%, on a random basis. Removed the set back,
problem is still intermittent, but appears to be less frequent. Tried
beating on anything related to power supply, both in normal and
trouble modes, no effects. I suspect something in the power supply
since both H & V are affected. Currently running the set with a
voltmeter on B+ which is running about 155V, waiting for something to
go wrong. But I can't sit around watching the set, just check it
intermittently. Anyone had similar problems with this or similar
Sonys. Photofact folder is 2564, putting manufacture date at sometime
in 1987 or early 1988. If anyone has a pdf of this folder, please let
me know.


Check for a bad 33uF 160 volt capacitor in the power supply.

Mark Z.

On Dec 28, 3:13*am, Sylvia Else wrote:
hr(bob) wrote:
Just had a Sony Model KV-1380R given to me a couple of days ago. *Only
problem is simultaneous but intermittent horizontal and vertical
shrinkage of about 20%, on a random basis. *Removed the set back,
problem is still intermittent, but appears to be less frequent. *Tried
beating on anything related to power supply, both in normal and
trouble modes, no effects. *I suspect something in the power supply
since both H & V are affected. *Currently running the set with a
voltmeter on B+ which is running about 155V, waiting for something to
go wrong. *But I can't sit around watching the set, just check it
intermittently. *Anyone had similar problems with this or similar
Sonys. Photofact folder is 2564, putting manufacture date at sometime
in 1987 or early 1988. *If anyone has a pdf of this folder, please let
me know.

Does the picture brightness remain the same?

Sylvia.

Yes, the brightness does not change. So far today the picture has
been ok every time I looked at it.

On Dec 28, 5:22*am, "Mark Zacharias"
wrote:
"hr(bob) " wrote in message

...

Just had a Sony Model KV-1380R given to me a couple of days ago. *Only
problem is simultaneous but intermittent horizontal and vertical
shrinkage of about 20%, on a random basis. *Removed the set back,
problem is still intermittent, but appears to be less frequent. *Tried
beating on anything related to power supply, both in normal and
trouble modes, no effects. *I suspect something in the power supply
since both H & V are affected. *Currently running the set with a
voltmeter on B+ which is running about 155V, waiting for something to
go wrong. *But I can't sit around watching the set, just check it
intermittently. *Anyone had similar problems with this or similar
Sonys. Photofact folder is 2564, putting manufacture date at sometime
in 1987 or early 1988. *If anyone has a pdf of this folder, please let
me know.

Check for a bad 33uF 160 volt capacitor in the power supply.

Mark Z.

So far I'm monitoring the output of the rectifiers on the AC power
line. If that voltage stays ok when there is a failure, I'll go to
the output of whatever regulator there is and start looking there.
The problem today is no failure at all. Hate intermittents!!!!

hr(bob) wrote:
On Dec 28, 3:13 am, Sylvia Else wrote:
hr(bob) wrote:
Just had a Sony Model KV-1380R given to me a couple of days ago. Only
problem is simultaneous but intermittent horizontal and vertical
shrinkage of about 20%, on a random basis. Removed the set back,
problem is still intermittent, but appears to be less frequent. Tried
beating on anything related to power supply, both in normal and
trouble modes, no effects. I suspect something in the power supply
since both H & V are affected. Currently running the set with a
voltmeter on B+ which is running about 155V, waiting for something to
go wrong. But I can't sit around watching the set, just check it
intermittently. Anyone had similar problems with this or similar
Sonys. Photofact folder is 2564, putting manufacture date at sometime
in 1987 or early 1988. If anyone has a pdf of this folder, please let
me know.
Does the picture brightness remain the same?

Sylvia.

Yes, the brightness does not change. So far today the picture has
been ok every time I looked at it.

Yet wouldn't one expect the brightness to increase noticeably if the
size decreases by 20%?

Sylvia.

On Sun, 27 Dec 2009 21:54:47 -0800 (PST), "hr(bob) "
put finger to keyboard and composed:

Just had a Sony Model KV-1380R given to me a couple of days ago. Only
problem is simultaneous but intermittent horizontal and vertical
shrinkage of about 20%, on a random basis.

It sounds like the EHT is increasing substantially. Does the set have
separate horizontal deflection and EHT generation circuits? Is there a
H-stat?

http://www.repairfaq.org/samnew/tvfaq/tvsonyhstat.htm

http://www.repairfaq.org/samnew/tvfaq/tvmohstat.htm

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.

Franc Zabkar wrote:
On Sun, 27 Dec 2009 21:54:47 -0800 (PST), "hr(bob) "
put finger to keyboard and composed:

Just had a Sony Model KV-1380R given to me a couple of days ago. Only
problem is simultaneous but intermittent horizontal and vertical
shrinkage of about 20%, on a random basis.

It sounds like the EHT is increasing substantially. Does the set have
separate horizontal deflection and EHT generation circuits? Is there a
H-stat?

http://www.repairfaq.org/samnew/tvfaq/tvsonyhstat.htm

http://www.repairfaq.org/samnew/tvfaq/tvmohstat.htm

- Franc Zabkar

Would also make the image brighter, wouldn't it?

Sylvia.

On Dec 28, 8:36*pm, Sylvia Else wrote:
Franc Zabkar wrote:
On Sun, 27 Dec 2009 21:54:47 -0800 (PST), "hr(bob) "
put finger to keyboard and composed:

Just had a Sony Model KV-1380R given to me a couple of days ago. *Only
problem is simultaneous but intermittent horizontal and vertical
shrinkage of about 20%, on a random basis.

It sounds like the EHT is increasing substantially. Does the set have
separate horizontal deflection and EHT generation circuits? Is there a
H-stat?

http://www.repairfaq.org/samnew/tvfaq/tvsonyhstat.htm

http://www.repairfaq.org/samnew/tvfaq/tvmohstat.htm

- Franc Zabkar

Would also make the image brighter, wouldn't it?

Sylvia.- Hide quoted text -

- Show quoted text -

Sylvia:

It might, it is hard to tell if the image gets brighter since I have
never actually seen it make the transition from normal to shrunk.

Franc:

I will put my HV probe on the CRT HV cap and see if it varies. It
must be going up quite a lot to make that much difference in the
picture size. From my old TV days over the past 54 years, it is
almost always the reverse, the HV goes lower, and the picture gets
dimmer and noticeable bigger (blooming we call it on the west side of
the pond).

hr(bob) wrote:
On Dec 28, 8:36 pm, Sylvia Else wrote:
Franc Zabkar wrote:
On Sun, 27 Dec 2009 21:54:47 -0800 (PST), "hr(bob) "
put finger to keyboard and composed:
Just had a Sony Model KV-1380R given to me a couple of days ago. Only
problem is simultaneous but intermittent horizontal and vertical
shrinkage of about 20%, on a random basis.
It sounds like the EHT is increasing substantially. Does the set have
separate horizontal deflection and EHT generation circuits? Is there a
H-stat?
http://www.repairfaq.org/samnew/tvfaq/tvsonyhstat.htm
http://www.repairfaq.org/samnew/tvfaq/tvmohstat.htm
- Franc Zabkar
Would also make the image brighter, wouldn't it?

Sylvia.- Hide quoted text -

- Show quoted text -

Sylvia:

It might, it is hard to tell if the image gets brighter since I have
never actually seen it make the transition from normal to shrunk.

Perhaps get a video camera and recorder on it? Would also tell you
whether the change is abrupt, or somewhat gradual, which you presumably
also don't yet know.

Sylvia.

On Tue, 29 Dec 2009 13:36:17 +1100, Sylvia Else
put finger to keyboard and composed:

Franc Zabkar wrote:
On Sun, 27 Dec 2009 21:54:47 -0800 (PST), "hr(bob) "
put finger to keyboard and composed:

Just had a Sony Model KV-1380R given to me a couple of days ago. Only
problem is simultaneous but intermittent horizontal and vertical
shrinkage of about 20%, on a random basis.

It sounds like the EHT is increasing substantially. Does the set have
separate horizontal deflection and EHT generation circuits? Is there a
H-stat?

http://www.repairfaq.org/samnew/tvfaq/tvsonyhstat.htm

http://www.repairfaq.org/samnew/tvfaq/tvmohstat.htm

- Franc Zabkar

Would also make the image brighter, wouldn't it?

Sylvia.

Yes, I would think so.

As for the effects on H & V size, if the set generates the EHT from
the line stage, then I'm finding it difficult to comprehend how the
size varies proportionately in both directions.

If the B+ were to increase, then the horizontal deflection current
would also tend to increase. However the vertical deflection current
should remain unchanged because there is a low ohm, current sensing,
feedback resistor in the yoke circuit. At the same time, the EHT would
increase and the raster would shrink.

AFAICs, the width should be far less affected than the height.

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.

Franc Zabkar wrote:
On Tue, 29 Dec 2009 13:36:17 +1100, Sylvia Else
put finger to keyboard and composed:

Franc Zabkar wrote:
On Sun, 27 Dec 2009 21:54:47 -0800 (PST), "hr(bob) "
put finger to keyboard and composed:

Just had a Sony Model KV-1380R given to me a couple of days ago. Only
problem is simultaneous but intermittent horizontal and vertical
shrinkage of about 20%, on a random basis.
It sounds like the EHT is increasing substantially. Does the set have
separate horizontal deflection and EHT generation circuits? Is there a
H-stat?

http://www.repairfaq.org/samnew/tvfaq/tvsonyhstat.htm

http://www.repairfaq.org/samnew/tvfaq/tvmohstat.htm

- Franc Zabkar
Would also make the image brighter, wouldn't it?

Sylvia.

Yes, I would think so.

As for the effects on H & V size, if the set generates the EHT from
the line stage, then I'm finding it difficult to comprehend how the
size varies proportionately in both directions.

If the B+ were to increase, then the horizontal deflection current
would also tend to increase. However the vertical deflection current
should remain unchanged because there is a low ohm, current sensing,
feedback resistor in the yoke circuit. At the same time, the EHT would
increase and the raster would shrink.

AFAICs, the width should be far less affected than the height.

- Franc Zabkar

What I had in mind when I asked the question I'm finding it difficult to
express properly. If people will allow me some lattitude in terminology
then, it seemed to me that some TVs, at least, contain a digital
processor which, amongst other things, allows control of the picture
size from a maintenance menu. If that processor was getting confused
about how big the picture should be - e.g. a digital bit has gone flaky
- then it could be adjusting the image size accordingly, but also
adjusting the beam current to maintain constant brightness.

Thus it seems to me that whether the brightness changes is an important
symptom.

Sylvia.

On Sun, 27 Dec 2009 21:54:47 -0800 (PST), "hr(bob) "
wrote:

Just had a Sony Model KV-1380R given to me a couple of days ago. Only
problem is simultaneous but intermittent horizontal and vertical
shrinkage of about 20%, on a random basis. Removed the set back,
problem is still intermittent, but appears to be less frequent. Tried
beating on anything related to power supply, both in normal and
trouble modes, no effects. I suspect something in the power supply
since both H & V are affected. Currently running the set with a
voltmeter on B+ which is running about 155V, waiting for something to
go wrong. But I can't sit around watching the set, just check it
intermittently. Anyone had similar problems with this or similar
Sonys. Photofact folder is 2564, putting manufacture date at sometime
in 1987 or early 1988. If anyone has a pdf of this folder, please let
me know.

My money would be on the STRXXXX voltage regulator that most Sony's of
that era had. They are a common failure, although they usually do go
intermittent.
Andy Cuffe

On Dec 28, 11:00*pm, Sylvia Else wrote:
hr(bob) wrote:
On Dec 28, 8:36 pm, Sylvia Else wrote:
Franc Zabkar wrote:
On Sun, 27 Dec 2009 21:54:47 -0800 (PST), "hr(bob) "
put finger to keyboard and composed:
Just had a Sony Model KV-1380R given to me a couple of days ago. *Only
problem is simultaneous but intermittent horizontal and vertical
shrinkage of about 20%, on a random basis.
It sounds like the EHT is increasing substantially. Does the set have
separate horizontal deflection and EHT generation circuits? Is there a
H-stat?
http://www.repairfaq.org/samnew/tvfaq/tvsonyhstat.htm
http://www.repairfaq.org/samnew/tvfaq/tvmohstat.htm
- Franc Zabkar
Would also make the image brighter, wouldn't it?

Sylvia.- Hide quoted text -

- Show quoted text -

Sylvia:

It might, it is hard to tell if the image gets brighter since I have
never actually seen it make the transition from normal to shrunk.

Perhaps get a video camera and recorder on it? Would also tell you
whether the change is abrupt, or somewhat gradual, which you presumably
also don't yet know.

Sylvia.- Hide quoted text -

- Show quoted text -

good point!

On Dec 29, 10:40*am, Andy Cuffe wrote:
On Sun, 27 Dec 2009 21:54:47 -0800 (PST), "hr(bob) "

wrote:
Just had a Sony Model KV-1380R given to me a couple of days ago. *Only
problem is simultaneous but intermittent horizontal and vertical
shrinkage of about 20%, on a random basis. *Removed the set back,
problem is still intermittent, but appears to be less frequent. *Tried
beating on anything related to power supply, both in normal and
trouble modes, no effects. *I suspect something in the power supply
since both H & V are affected. *Currently running the set with a
voltmeter on B+ which is running about 155V, waiting for something to
go wrong. *But I can't sit around watching the set, just check it
intermittently. *Anyone had similar problems with this or similar
Sonys. Photofact folder is 2564, putting manufacture date at sometime
in 1987 or early 1988. *If anyone has a pdf of this folder, please let
me know.

My money would be on the STRXXXX voltage regulator that most Sony's of
that era had. *They are a common failure, although they usually do go
intermittent. *
Andy Cuffe



Today the picture had shrunk when I went to my workshop. The
rectified line voltage had risen to 150 V from 140 V when the picture
was full-size. This might be due to a decreased load on the power
supply since the scanning current has gone down. Next thing to do
will be to see what if anything I can do about turning the set off and
on after a failure and see if the picture restores to correct size or
not. This seems to be a bottom-line Sony, so I don't know if there is
anything adjustable from a memory chip that might affect the picture.
I am also going to move my voltmeter to the CRT cap and see what the
HV does when the failure occurs. Stay tuned!

On Tue, 29 Dec 2009 18:17:47 -0800 (PST), "hr(bob) "
wrote:

On Dec 29, 10:40*am, Andy Cuffe wrote:
On Sun, 27 Dec 2009 21:54:47 -0800 (PST), "hr(bob) "

wrote:
Just had a Sony Model KV-1380R given to me a couple of days ago. *Only
problem is simultaneous but intermittent horizontal and vertical
shrinkage of about 20%, on a random basis. *Removed the set back,
problem is still intermittent, but appears to be less frequent. *Tried
beating on anything related to power supply, both in normal and
trouble modes, no effects. *I suspect something in the power supply
since both H & V are affected. *Currently running the set with a
voltmeter on B+ which is running about 155V, waiting for something to
go wrong. *But I can't sit around watching the set, just check it
intermittently. *Anyone had similar problems with this or similar
Sonys. Photofact folder is 2564, putting manufacture date at sometime
in 1987 or early 1988. *If anyone has a pdf of this folder, please let
me know.

My money would be on the STRXXXX voltage regulator that most Sony's of
that era had. *They are a common failure, although they usually do go
intermittent. *
Andy Cuffe



Today the picture had shrunk when I went to my workshop. The
rectified line voltage had risen to 150 V from 140 V when the picture
was full-size. This might be due to a decreased load on the power
supply since the scanning current has gone down. Next thing to do
will be to see what if anything I can do about turning the set off and
on after a failure and see if the picture restores to correct size or
not. This seems to be a bottom-line Sony, so I don't know if there is
anything adjustable from a memory chip that might affect the picture.
I am also going to move my voltmeter to the CRT cap and see what the
HV does when the failure occurs. Stay tuned

This unit doesn't have adjustments stored in a EEprom. Mark
Zacharias' solution is the most common failure mode causing this
symptom. Rarely the STR IC goes intermittent and even rarer, a
resistor changes value in the regulator circuit. I'd replace the 33
uf cap he mentioned before further troubleshooting. Chuck