Lighter horizontal line on Sony TV
 

"Marco De Vitis" wrote in message
...
Hi, I have a KV-X2531A Sony TV (chassis AE-1C) which is recently
showing a lighter horizontal area on the top of the screen, a line
placed more or less 1/4 of the total screen size from the top.
It appears after 10 minutes or so, when the TV gets hot.

Actually, the area seems to be slightly distorted, as if the lighter
line is indeed the result of an "accumulation" of horizontal lines.

BTW, the TV is the same where I had the disappearing color problem,
see my old thread "Intermittent color/bw on Sony TV".
Some time ago I swapped the two variable capacitors near the
oscillators to work around the color problem, and everthing went
perfect for a while. Recently, the strange line appeared.

Today I tried swapping the capacitors back to their original
positions, but the situation is exactly the same: the color is ok, but
the line is still there.

What might be causing this? I didn't touch the capacitor values... can
their swapping be related to the new problem? Or is it a new and
totally unrelated problem?

Thanks in advance.

--
Ciao,
Marco.

Sounds like bad caps in the vertical output stage.

Lighter horizontal line on Sony TV
 

Il 19/08/2003, alle ore 15:50, Marco De Vitis ha scritto:

Today I tried swapping the capacitors back to their original
positions, but the situation is exactly the same: the color is ok, but
the line is still there.

Just for the record, soon after writing my message the line
disappeared, everything seems ok now.
Who knows... I might guess it was some kind of leftover from the
previous situation (the two swapped capacitors), but it sounds to me
like nonsense. :)

--
Ciao,
Marco.

...."Dig?", Bill Bruford's Earthworks 1989

Lighter horizontal line on Sony TV
 

I have the very same problem on a KV29 100Hz (FX chassis).
The upper part of the screen is "folded" on itself.

The first symptomI got was no vertical deflection at all. I got just a very
brigth horizontal line in the middle of the screen.
I found that the resistors in series to the output transistor where "well
done!".
I replaced them with a couple of higher wattage resistors mounted on a
small headsink and the screen was back apart for that strange "fold".
I found that a capacitor was also damaged (a 3.3uF filter capacitor
on the supply line of the above PNP/NPN couple) and also a diode
in the same area was leaky. On my chassis the resistors were called
R458/R459, the capacitor is C524 and the diode is D506.
All of them are in the vertical drive stage.

I bet you have the same problem.

Good luck
Fabio



"Marco De Vitis" ha scritto nel messaggio
...
Hi, I have a KV-X2531A Sony TV (chassis AE-1C) which is recently
showing a lighter horizontal area on the top of the screen, a line
placed more or less 1/4 of the total screen size from the top.
It appears after 10 minutes or so, when the TV gets hot.

Actually, the area seems to be slightly distorted, as if the lighter
line is indeed the result of an "accumulation" of horizontal lines.

BTW, the TV is the same where I had the disappearing color problem,
see my old thread "Intermittent color/bw on Sony TV".
Some time ago I swapped the two variable capacitors near the
oscillators to work around the color problem, and everthing went
perfect for a while. Recently, the strange line appeared.

Today I tried swapping the capacitors back to their original
positions, but the situation is exactly the same: the color is ok, but
the line is still there.

What might be causing this? I didn't touch the capacitor values... can
their swapping be related to the new problem? Or is it a new and
totally unrelated problem?

Thanks in advance.

--
Ciao,
Marco.

..."The Juliet Letters", Elvis Costello & The Brodsky Quartet 1993