Sony TV vertical linearity problem
 

Hello,
I own a Sony KV-X2531A TV set which has a video problem, I suppose related
to vertical deflection.

There's an area in the upper half of the screen where horizontal lines are
not evenly distributed, causing excessive brigthness and image
deformation.
And, also, the image does not reach the bottom of the screen, leaving a
black empty area below.

You can see an example he http://www.icuccioli.it/sony-vertlin.jpg

The example shows the problem in its "stable" state, some minutes after
the TV has been turned on (it then stays like this for hours, until turned
off). But it is MUCH more evident immediately after the TV is turned on,
showing a very squashed image.

What would you suggest? Maybe a capacitor needs to be replaced? The fact
that the problem also shows up as soon as the TV is turned on doesn't make
me feel like cold solders are the reason for it.
Where should I look? I have the TV schemes available.

Thanks a lot in advance.

--
Ciao,
Marco.

...."You Had It Coming", Jeff Beck 2001

"Marco De Vitis" wrote in message
...
Hello,
I own a Sony KV-X2531A TV set which has a video problem, I suppose related
to vertical deflection.

There's an area in the upper half of the screen where horizontal lines are
not evenly distributed, causing excessive brigthness and image
deformation.
And, also, the image does not reach the bottom of the screen, leaving a
black empty area below.

You can see an example he http://www.icuccioli.it/sony-vertlin.jpg

The example shows the problem in its "stable" state, some minutes after
the TV has been turned on (it then stays like this for hours, until turned
off). But it is MUCH more evident immediately after the TV is turned on,
showing a very squashed image.

What would you suggest? Maybe a capacitor needs to be replaced? The fact
that the problem also shows up as soon as the TV is turned on doesn't make
me feel like cold solders are the reason for it.
Where should I look? I have the TV schemes available.

Thanks a lot in advance.

--
Ciao,
Marco.

..."You Had It Coming", Jeff Beck 2001

Hi,

I think this problem was caused by the 680uF capacitor in the scan coupling
circuit as I remember C531? - if not check the 27V supply.

Philip

You need to properly test the capacitors in the vertical deflection
circuit. Start at the output device, if that does not find the
problem, go back further to the vertical sweep waveform generation.

David

Marco De Vitis wrote in message ...
Hello,
I own a Sony KV-X2531A TV set which has a video problem, I suppose related
to vertical deflection.

There's an area in the upper half of the screen where horizontal lines are
not evenly distributed, causing excessive brigthness and image
deformation.
And, also, the image does not reach the bottom of the screen, leaving a
black empty area below.

You can see an example he http://www.icuccioli.it/sony-vertlin.jpg

The example shows the problem in its "stable" state, some minutes after
the TV has been turned on (it then stays like this for hours, until turned
off). But it is MUCH more evident immediately after the TV is turned on,
showing a very squashed image.

What would you suggest? Maybe a capacitor needs to be replaced? The fact
that the problem also shows up as soon as the TV is turned on doesn't make
me feel like cold solders are the reason for it.
Where should I look? I have the TV schemes available.

Thanks a lot in advance.

Usual story -- check and replace any suspect/faulty electrolytic caps the
the power supply and vertical deflection areas.

"Marco De Vitis" wrote in message
...
Hello,
I own a Sony KV-X2531A TV set which has a video problem, I suppose related
to vertical deflection.

There's an area in the upper half of the screen where horizontal lines are
not evenly distributed, causing excessive brigthness and image
deformation.
And, also, the image does not reach the bottom of the screen, leaving a
black empty area below.

You can see an example he http://www.icuccioli.it/sony-vertlin.jpg

The example shows the problem in its "stable" state, some minutes after
the TV has been turned on (it then stays like this for hours, until turned
off). But it is MUCH more evident immediately after the TV is turned on,
showing a very squashed image.

What would you suggest? Maybe a capacitor needs to be replaced? The fact
that the problem also shows up as soon as the TV is turned on doesn't make
me feel like cold solders are the reason for it.
Where should I look? I have the TV schemes available.

Thanks a lot in advance.

--
Ciao,
Marco.

..."You Had It Coming", Jeff Beck 2001