Samsung Plasma power supply, blown standby IC

[PowerAmpFreak]

Re: Samsung Plasma power supply, blown standby IC

Do you know WHAT is wrong with T3S? Is the primary open circuit?

[trosdepep]

Re: Samsung Plasma power supply, blown standby IC

In the service manual you can see the T3S. All coils are continuous except for pins 1 and 2 of primary.

[PowerAmpFreak]

Re: Samsung Plasma power supply, blown standby IC

If you're familiar with transformers you might check how the primary is wound, try to let some of the tape off and check if the primary is visible. Eventually, the primary is split in two windings, then it will be harder to repair it. If you're lucky you can see where the primary has shot off and again if you're lucky, eventually solder the wires back.
If you're unlucky, the primary is wound as the layer closest to the core and you have to wind off all the secondaries which will be a hard work unfortunately.

This is really nothing for the unexperienced.

[trosdepep]

Re: Samsung Plasma power supply, blown standby IC

PowerAmpFreak many thanks for your advice. I was lucky and was on the outside coil. I've been able to weld easily. Now mark 0.5 ohms YUHUUUU!!!!
Well, now I have to make the order of the break components:
F9,R2, IC2, C268, C51
I think these also will change in case:
C37, C38, C50 they are around of the explosion

I think they came in 1week.
I'll keep you informed of my fight

Thanks a lot.

Regards.

Pepe.

[trosdepep]

Re: Samsung Plasma power supply, blown standby IC

I have put new components:
F9, R2 (0.69ohm, original is 0,5ohms), Ic2, C268, C51 and C100.
No works!!! and boooommm!!! C100 explodes!! Nooooo! its wrong polarity!!
I put another new one right polarity. No works, no explosions. There is 235V on C100, no volts on transformer, pin7 of Ic2 marks 9,10, 11, 12, 9, 10 ,11....volts
I check the area again, zd900 is shorted!!. (I think that is 8,8V zener)
I extract de diode and and plug again, but now begins to smell of burning. Unplug quickly Ic2 is very hot.

Tomorrow I will put new components, all caps (C37, C38, C50 too) ZD900 (8,8V) and ic2 and will try....

[selldoor]

Re: Samsung Plasma power supply, blown standby IC

You might want to consider making one of these instead of burning parts out.
http://antiqueradio.org/dimbulb.htm

[trosdepep]

Re: Samsung Plasma power supply, blown standby IC

I'm back to change all these components:
C50, C51, C36, C37, C38, C46, C268, IC2 and ZD900 (8,2V zener) (I dont know why it is not in the diagram), R2 is ok (0,69 ohms)
I have connected the tv with a 15w bulb in series. The bulb lights.
Now I try with a 40w bulb. First lights and a pair of second begins to fade gradually, then I disconnect quickly and IC2 is hot, no a lot, but i think that if I don´t disconnect it burns.
What happen? Is R2 0,69ohms right value, original is 0,5 ohms?... Is possible transformer not right?: I've fixed welding a transformer coil, but do not know the correct value, now marks 0.0 ohms (pins 1,2), pins 3,4 0.3 ohms, pins 5,6 1.5 ohms and secondary pins 10,7 0.0 ohms,

I´m lost... I think problem is transformer...

PS: When I was repairing the transformer broke the part that looks yellow in the pic below but I stuck with loctite...

[tom66]

Re: Samsung Plasma power supply, blown standby IC

If you cracked the core, the transformer needs to be replaced.

[trosdepep]

Re: Samsung Plasma power supply, blown standby IC

I have been researching on the subject and what is broke is the ferrite core.
Some say that sticking is enough but others say no, and if it sticks, it quickly degrades and destroys.

Anyway I'm not sure that the circuit is ok with a new transformer ....
I think this ends my adventure. Next time take more care with the ferrite cores.

Thank you very much for your advice.

See you at the next repair.

Regards.
Pepe.

[raffaelecont]

Re: Samsung Plasma power supply, blown standby IC

salve sono nuovo di questo forum ho un grandissimo problema al plasma in questione mi è saltato i componenti IC2, R2, C268, C51 cambiati risaltano il problema è sul negativo ic2 salta il piedino 5 aiutooooooo

[raffaelecont]

Re: Samsung Plasma power supply, blown standby IC

salve ho risolto il problema dell ic2 ora ho 18volt ovunque suggerimenti?grazie