Hi,
Thanks to `Inty` and `default` for replies.
The fuses all check fine, unless I am not seeing all of them. I am
familiar with fuse-resistors, too.
Update: I changed the 3 electrolytics in the vertical circuits (100mfd
at approx 35V), and they did not help. I checked the caps that I
removed, and all were close to 100mfd (the weakest tested 88 mfd).
Talked to 2 guys (my original source, and another guy that I know who
was in the tv sales/service business for many years), and both guys
believe that 99% likelihood that the problem is defective TA8427K
vertical deflector chip. Both guys said this part goes bad regularly.
So I have already unsoldered it, and have ordered a replacement. Cheap
solution if it works. Less than $8 including postage for a real
Toshiba chip. Should arrive in a few days. If that does not fix it,
we'll go from there.
The only thing that I wonder about, is that my friend asked me to check
whether there is 24V from pin 6 to ground on TA8427K. Well, I got 0,
although it was `damn hard` to get a reading in that area of the board
while the set was operating. It is possible I was not getting good
contact with my meter. Assuming the 0 is accurate, he says that means
something else is wrong, although he feels that the chip is probably
bad also (which he originally said I should replace). So I Look around
on the board, there is not many components in that area. A diode goes
directly to pin 6 of TA8427K, and a bunch of other diodes are in the
immediate area (all diodes checked normal once I removed the TA8427K),
and of course the 100mfd caps (replaced), and a couple mica caps (very
unlikely to be defective). There is 1 glass fuse in the area, which is
good. He asked me to look for small black square boxes, which he says
would be fuses. There is none of them. I can easily identify the
components in the area, so I really cannot see any way that I am
missing a fuse anywhere. This might be a lot easier with a schematic,
but I doubt at this point it would tell me a whole lot.
I'll know more once the vertical deflector chip has been replaced.
Thanks again.
Inty XP wrote:
In data Sun, 25 Jun 2006 17:24:49 +0200, default ha scritto:
(closeup of area that may be the problem...)
http://mysite.verizon.net/cowman136/tv2.jpg
This is the flyback transformer area. If the design has the vertical
circuits power supplied by the flyback, then your height shrinkage could
be
a premature sign the flyback is breaking down, or there could be a
problem
only in the vertical circuit....changing all capacitors in the vertical
circuit is a common solution to certical problems, however the flyback
xfmr
in that chassis is common fail\, so its of not it be mentioned.
MAYBE a blown fuse resistor?
--
Inty.Evolution
- per email normali e con immagini Jpeg