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Faint Horizontal lines on top 1/4 of television screen

J

Jon Danniken

Jan 1, 1970
0
Hello,

I have an old Montgomery Wards (Sharp) television, model JSJ2220. It has the
problem of a number of faint horizontal lines in the top 1/4 of the screen.
Some of the lower lines have brighter "dashes" in them, some of which blink.
At the bottom of the lines is one line that is composed of colors like a
rainbow.

I have searched the group, and read that problems of this type are often
attributed to electrolytics in the Vertical section. Unfortunately, I do not
have a schematic, and the circuit board isn't laid out with a diagram
showing roughly what does what.

If you have any suggestions as to what the problem might be, or which
components would likely be the culprits, I would be most appreciative.

Thank you,

Jon
 
J

Jon Danniken

Jan 1, 1970
0
Jon Danniken said:
I have an old Montgomery Wards (Sharp) television, model JSJ2220.

CORRECTION: model number JSJ12220

Sorry for the mistake.


Jon
 
M

Mark D. Zacharias

Jan 1, 1970
0
Bad boost capacitor in the vertical circuit. The vertical output will fail
soon if not fixed - it's presently running too hot.

Mark Z.
 
J

Jon Danniken

Jan 1, 1970
0
Thanks Mark. Any idea which capacitor it is? I don't have a schematic for
the unit.

Jon
 
C

crazy frog

Jan 1, 1970
0
look at the caps near anything hot or
burnd spots, my tv did this 2
 
M

Mark D. Zacharias

Jan 1, 1970
0
Lots are in the range of 100uF at 35 volts, near the vertical output. This
is all just generic advice, BTW - don't know your model.

Mark Z.
 
T

Tom MacIntyre

Jan 1, 1970
0
Lots are in the range of 100uF at 35 volts, near the vertical output. This
is all just generic advice, BTW - don't know your model.

Mark Z.

....but your advice will be dead on correct. :)

Tom
 
A

Asimov

Jan 1, 1970
0
"Jon Danniken" bravely wrote to "All" (07 Oct 05 19:14:05)
--- on the heady topic of "Re: Faint Horizontal lines on top 1/4 of television screen (model corre"


Replace *all* electros around a 1" vicinity of the vertical IC. Cost
of the electros is minimal and one might not have to go back in there
for longer a while than if we just replaced the faulty one. Consider
that commonly it takes more time to take things apart than to actually
make a repair.

A*s*i*m*o*v


JD> From: "Jon Danniken" <[email protected]>
JD> Xref: core-easynews sci.electronics.repair:344431

JD> Thanks Mark. Any idea which capacitor it is? I don't have a
JD> schematic for the unit.

JD> Jon

.... If all else fails, hurl it across the room a few times!
 
B

buran

Jan 1, 1970
0
It's a good idea to change all the electrolytic caps in the vertical
deflection.

I.
 
J

Jon Danniken

Jan 1, 1970
0
Mark D. Zacharias said:
Lots are in the range of 100uF at 35 volts, near the vertical output. This
is all just generic advice, BTW - don't know your model.

Thank you Mark, and others. I located my Vertical IC (don't laugh), a
uPC1378 variant, as well as five different electrolytics in the section.
One of these is actually a 100uF at 35 volts, just as you predicted.

Am I going to want to special order a "low ESR" cap for a replacement? My
local parts store only carries "regular" caps; otherwise I'll have to go
through digikey.

Thanks again, and I apologize for the delayed response to this.

Jon
 
T

Tom MacIntyre

Jan 1, 1970
0
Thank you Mark, and others. I located my Vertical IC (don't laugh), a
uPC1378 variant, as well as five different electrolytics in the section.
One of these is actually a 100uF at 35 volts, just as you predicted.

Am I going to want to special order a "low ESR" cap for a replacement? My
local parts store only carries "regular" caps; otherwise I'll have to go
through digikey.

Thanks again, and I apologize for the delayed response to this.

Jon

Get the 105 degrees C version at least. Low ESR likely isn't
important.

Tom
 
J

Jon Danniken

Jan 1, 1970
0
Tom MacIntyre said:
Get the 105 degrees C version at least. Low ESR likely isn't
important.

Thanks, Tom. I ended up ordering the batch through digikey, low ESR 105C
jobs, since they were about as cheap as the other ones anyway. The only
outlet in town had the same old dried up electrolytics they've had for the
last 10 years, and the TV repair place wanted $7.20 for just *one* cap (I
guess that's their way of saying they don't want to sell me caps, lol).

Jon
 
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