Thanks! I'll check that! Any ideas as to why that would cause a buzz in
the neck of the picture tube? tia
wrote:
There is a bad capacitor in one of the video switch circuits. The ic
and parts are near one corner of the small signal part of the board.
It has been 6 years since I saw this problem. It was a video signal
coupling capacitor as I remember.

David

Floyd Gilmour wrote:
Hi, I have read a bunch of posts about the capacitors on circa
1990s
Mits but this set is different from most of the posts I've read.
This
one has the 930B436 PIP (no bypass?) which does NOT have the
surface
mount caps and I've replaced just about all of the electrolytics in
the
set, I think I only have a few BP I can still replace. I have been
battling the inverted video (no luma high chroma) on my set now for
about 6 months and it seems to get better for 30 days at a time.
Since
the failures started I have also had another symptom which is a
fairly
loud audible buzz not from the speakers, but from the neck of the
picture tube. I have found that if you swith the channel back and
forth
several times you can get something to sync and the buzz goes away.
Reseting the power also seems to work sometimes. On my last round
of
capacitors (about 30) I again have a great picture but I still get
that buzz intermittently. I have a few areas where the traces were
compromised by the acid and I've had to make repairs but everything
seems sound. I read on a couple of posts about the neck of the
picture
tube actually cracking which concerns me. This set came to me used
with
a vertical problem (fixed with 5 capacitors) and I only have about
$50
in caps in it plus the picture is great when it works, so I
definately
want to get it fixed. For anyone reading this take the time and
check
ALL of the capacitors as in every section there have been many
"fishy"
caps if not just plain gunk leakin'! The condition of some of these
caps was so bad, it's surprising that the crazy thing could run at
all.
If anyone has any tips to get rid of this buzz for good I sure
would
appreciate it. Thanks!