Sharp 25J-S100 TV: Loud blasts of static in audio channels, fuzzy picture
 

Greetings!

On this Sharp 25J-S100 TV, I get intermittent blasts of static in the
audio channels. These blasts occur at the same time as an audible click
is heard inside the set. Immediately before this happens, however,
parts of the screen will go out of focus and appear washed out. I
suspected electrostatic discharge from the tube, but the grounding
strap is held on tight.

Anyone have any ideas?

Thanks,
Baral'heia

wrote in message
oups.com...
| Greetings!
|
| On this Sharp 25J-S100 TV, I get intermittent blasts of static in the
| audio channels. These blasts occur at the same time as an audible click
| is heard inside the set. Immediately before this happens, however,
| parts of the screen will go out of focus and appear washed out. I
| suspected electrostatic discharge from the tube, but the grounding
| strap is held on tight.

Lots of places can arc over. I'd look at the flyback.

N

I really only know basic electronics, and not much at that... so I'm
not sure that I know what I'm looking for. I've looked the main board
over (p/n DUNTK9254WE) and aside from some darkened spots underneath
large 1/2W (?) resistors, nothing looks out of the ordinary. As for the
flyback transformer, nothing appears amiss about it either... but once
again, I don't totally know what I'm looking for.

Regarding the arcing... I assume I need to have the set powered on with
the case opened to do that. How should I do that - i.e. is it okay to
have the set laying on it's face, or does it need to be upright like it
would be normally, etc?

Thanks for the help!
Baral'heia

Time will tell, but I might have fixed it quite simply. The rubber
wedges that Sharp uses to stablize the whole assembly on the end of the
picture tube had begun to fall out. The tape still held them to the
tube, but the rubber pieces were no longer inserted under the assembly.
I pushed them firmly back into place, adjusted the picture slightly,
and so far (30 minutes), it hasn't made the noise. Here's hoping it
stays static-blast free. ^_^

Baral'heia

Nope, didn't really affect it. I notice that the TV does not really
begin to exhibit these symptoms until more than 25% of the screen is
red (or more than 50% yellow). For instance, when watching the show
"Futurama", the TV will begin doing it's static blast thing when Dr.
Zoidberg, the red lobster guy, is shown on screen.

Ideas, anyone?

Nope, didn't really affect it. I notice that the TV does not really
begin to exhibit these symptoms until more than 25% of the screen is
red (or more than 50% yellow). For instance, when watching the show
"Futurama", the TV will begin doing it's static blast thing when Dr.
Zoidberg, the red lobster guy, is shown on screen.
Ideas, anyone?
Baral'heia

possibly a power supply fault since pic and sound are affected. how old
is the set? if its got a few years on it you may have to replace the
capacitors in the low voltage section

-Ben

The set was manufactured in December of 1997, so it's about 7 years
old. Only seen use for about 5-6 years, though. For a while it was on
continuously, for more than a month or so, I believe.

One thing I forgot to mention is when the TV freaks out, the red tears
toward the right side of the screen, and each click/static blast causes
the picture to jump and flash and stuff.

What can I do first before I start ripping caps off the board? I would
get in there and flex the board a bit and stuff, if I knew what the
heck I was doing, lol. If I did have to start replacing caps, I'd just
need to replace the electrolytic ones, and most of those have their
values printed on them, right?

Thanks,
Baral'heia