You will need to purchase the service manual to continue. The TV set
can get complicate to troubleshoot. I am assuming you have the
experience, tools, and knowledge to service your set.

It is impossible to guess what can be wrong. There are many things in
the set that can cause the power supply to go in to the protect mode.


Jerry G.
======







Ludo wrote:
When I first got this little (10yo?) beauty, the screen would intermittently
turn black before the set switched itself to standby. It would readily come
up again by pressing a channel. If you were uick enough, juggling the power
connection from the F1 to the A board would usually bring the picture back
before it went on standby. Examining the shiny side of the A board revealed
at least 4 or 5 cracked solder points. After redoing them the set worked
perfectly for two days. The next evening, without having touched anything,
it had a "ragged" edge on the left of the screen, occasionally distorting
the whole screen. This only happened on the lower VHF channels. It was
hardly noticeable on UHF. Interestingly (probably not for the neighbours)
that interference, when it happened, was picked up by any TV or VCR tuner in
the vicinity ! Occasionally the set would be perfect for up to 20 minutes. I
suspected another dodgy joint, but couldn't find one. A few days later the
TV shut down and the only life remaining, apart from the degaussing, is a
faint click, click, ... when putting the power on. It doesn't even go in
standby. Next, I did find another (hidden) cracked soldering at the HOT
transformer, which being right next to the tuner may well have been the
cause of the "interference" problem.
From what I've read in the many postings I know that something is preventing
the power supply to come up, but I haven't got a clue where to start. The
HOT (in situ) has 20 Ohms between b and c and also between e and c in
either direction. Between b and e, I've only got a few Ohms. I can't easily
isolate the power supply because the lot is on the one board (A). I don't
have a variac, besides I wouldn't know what voltages - where - to expect. I
just think the set is too good to go to landfill, because the picture is
really good and the sound is much better than my previous Sony. Perhaps
someone can put me in the right direction after reading the earlier
symptoms. Even shedding some light on the Sony numbering system would help.
So far I've been searching for KV29, but that seems only to point to the
size of the screen.

Cheers,

Ludo.