"Peabody" wrote in message
...
I have JVC model AV-27920 television that goes back a few years.

A few months ago, I began having a problem at the top of the screen.
It's hard to describe, but it looks like to top part of the image is
folded over and displayed upside down. I guess it looks like the
the vertical isn't quite making it all the way to the top before the
lines start being displayed.

At first this occurred only when the TV was first turned on,
affecting the top couple inches. As the set warmed up over 10
minutes or so, this would gradually shrink, and finally all
disappear, and everything looked normal. Nothing strange happens at
the bottom fo the screen.

Now, the foldover when cold covers more of the screen, and it no
longer goes away completely when warm.

I actually have the Sams schematic on this from folder 4080, and I'm
hoping that whatever is failing is something I can replace. An
electrolytic maybe?

I don't have any test equipment, but am competent to remove, test,
and replace things. So perhaps someone can suggest what to look
for. I would appreciate any educated suggestions, either in general
or with reference to functions I can find on the schematic.

Thanks very much.


Electrolytic capacitors around the vertical output IC, they'll be smallish,
probably 1-10 uF at about 50V and usually there will be 2 or 3 that need
replacing.

"Peabody" wrote in message
...
Peabody says...

Electrolytic capacitors around the vertical output IC,
they'll be smallish, probably 1-10 uF at about 50V and
usually there will be 2 or 3 that need replacing.

Thanks very much. The vertical output IC is an LA7832,
and the only electrolytic I see on the schematic is a
100 uf between pins 3 and 7.

However, looking back a step to the giant 56-pin IC201,
a TA1242N "decoder", there are 2.2 uf electrolytics
coming off of pins 24 (V Ramp) and 25 (V Sep Filter).

I'll check those out and see where that leads me.
Thanks again for the suggestion.

For those who might see this thread in the future, I wanted
to report that I replaced these capacitors, both of which
were very near the vertical output IC:

C424 100uF/35V
C425 440uF/35V

And now it works. Both of the caps I removed appear to test
ok per my primitive analog voltmeter method, so I suppose
it's possible both were good and the fix was just a
coincidental result of disassembly/reassembly. We'll never
know for sure.

And again for the record, this was a JVC model AV-27920.

$2.80, plus gas money to drive to Radio Shack and back. I
just love it when things end this way.

Thanks very much for the help.



Thats amazing, you found the caps you needed at rat shack! They have so few
components these days.