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Interesting Flyback problem MTC 28" TV

M

Myron Samila

Jan 1, 1970
0
Hey all,

I've got an old MTC 28" tv that I'm working on. (model MTV-2800C)

The flyback is a KFS60490A which crosses to a HR 8562

Anyhow, the set has a HV shut down problem. You can hear a tiny arc, zapping once in a
while. Well, on the flyback are the red tube wire, and the black ground wire. There is a
small red wire that also enters the flyback, well..... I brought a screwdriver close to
the flyback to move the small lead wires away from the actual flyback and ZAP! total shut
down.

If I move all the small wires away from the flyback, the zapping goes away. I'd love to
replace the flyback, maybe the insulation inside has broken down?!?

I put some high voltage insulating tape around the area where the spark jumps to the screw
driver (which instantly was grounded to the next available ground wire). This has seemed
to help quite a bit. Otherwise the set works perfect.

Once again, ideally a replacement flyback (cheap) is what I'm after. I can't source one
out, I prefer finding one in Canada (at a good price, if the flyback is $80, it may not be
worth repairing).

The HV circuit seems to work fine otherwise, MTC btw is no longer around. The were sold
off to Grandetel, which I think is also gone as well.

Any suggestions, temp fix? (HV RTV compound?-yeah.... ummm)

There area few caps I need to change, they are visibly overheated and are probably open
at this point. But this is only affecting the picture, it is no where near in the HV
circuit.

Any help would be appreciated, cheers!!
 
K

Ken Weitzel

Jan 1, 1970
0
Myron said:
Hey all,

I've got an old MTC 28" tv that I'm working on. (model MTV-2800C)

The flyback is a KFS60490A which crosses to a HR 8562

Anyhow, the set has a HV shut down problem. You can hear a tiny arc, zapping once in a
while. Well, on the flyback are the red tube wire, and the black ground wire. There is a
small red wire that also enters the flyback, well..... I brought a screwdriver close to
the flyback to move the small lead wires away from the actual flyback and ZAP! total shut
down.

If I move all the small wires away from the flyback, the zapping goes away. I'd love to
replace the flyback, maybe the insulation inside has broken down?!?

I put some high voltage insulating tape around the area where the spark jumps to the screw
driver (which instantly was grounded to the next available ground wire). This has seemed
to help quite a bit. Otherwise the set works perfect.

Once again, ideally a replacement flyback (cheap) is what I'm after. I can't source one
out, I prefer finding one in Canada (at a good price, if the flyback is $80, it may not be
worth repairing).

The HV circuit seems to work fine otherwise, MTC btw is no longer around. The were sold
off to Grandetel, which I think is also gone as well.

Any suggestions, temp fix? (HV RTV compound?-yeah.... ummm)

There area few caps I need to change, they are visibly overheated and are probably open
at this point. But this is only affecting the picture, it is no where near in the HV
circuit.

Any help would be appreciated, cheers!!

It might be worth investigating high voltage putty.

Better by far than tape, because it leaves no air gaps,
and you can put it on as thickly as you like (or can
afford :)

I know that at least one of the manufacturers was
General Cement.

Take care.

Ken
 
M

Myron Samila

Jan 1, 1970
0
Ken Weitzel said:
It might be worth investigating high voltage putty.

Better by far than tape, because it leaves no air gaps,
and you can put it on as thickly as you like (or can
afford :)

I know that at least one of the manufacturers was
General Cement.

Take care.

Ken

That actually does sound like a viable idea.

Turns out my problem isn't so interesting. It is shorting out (arcing) from the
"screen/focus" area, way above it, you can still adjust it, but where the lead exits the
flyback, this is where it can short to the nearest ground conductor.

I may insulate it, and re-route the wires near the flyback. This should solve the trouble
for a while, since the set works fine otherwise.

Finding this flyback would not be easy.
 
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