Sofa Slug wrote:
Doug Greenberg wrote:
Hello,
We have an elderly JVC 27-inch tube-type television, Model AV-27BMS
(I think). It's been a good TV for 13 years now (manufacturing date
is January 1995). In the last few months, however, it has developed
an annoying problem. The picture periodically shrinks down
horizontally (that is, the screen turns dark above and below, and
what's left is a thin, squished-down picture perhaps three or four
inches tall).

If someone bangs lightly on the side of the TV the picture returns to
normal--for a while. But the problem doesn't go away and it actually
has gotten worse.

Any ideas of what would cause this, and just as important, is this a
problem that likely can be fixed for significantly less than the price
of replacing the television? Bringing this heavy sucker to a repair
shop would be no pleasure, but if the problem seems manageable, by
gosh I'll do it.

Doug in Berkeley


I have a similar 27" JVC TV, model AV-27770. It had the exact same
symptoms, including banging on it for a temporary "fix". The problem was
a bad solder joint on the CRT socket's PC board.

Look at all the PC boards with a magnifying glass for joints that have a
cracked "ring" around the connection. This happens from heat & age, and
seems to be fairly common on items like this.



No way a solder joint on the CRT socket board affected vertical
deflection, nothing in the deflection circuit routes through that board.
The mechanical stresses of taking the set apart and putting it back
together may have "fixed" the bad joint in the deflection though.