LG 50PJ350 plasma blowing Y-Sustain board

[zape]

Re: LG 50PJ350 plasma blowing Y-Sustain board

Yeah I wish @tom66 was more active these days I saw his old posts around plasmas were very helpful.

[zape]

Re: LG 50PJ350 plasma blowing Y-Sustain board

Tried to fix my TV today again.
Replaced fets, turning on, a few seconds, magic smoke, and all 6 fets on y-sus are blown again, along with R503
Sadly, but this is my first TV (out of ~20) which I could not fix.

[Biruslapio]

Re: LG 50PJ350 plasma blowing Y-Sustain board

That's the problem with LG plasmas mostly, if you don't fix everything, it goes boom on power up most of the time, Panasonic has more protections embedded, don't know about Samsung.

The most annoying thing with plasma repair are the fake IGBTs, it's making me give up on repairing these types of TVs.

[Keshenatech1]

Re: LG 50PJ350 plasma blowing Y-Sustain board

@Zape: I know it's frustrating but if it's any consolation I blew mine up 3 times before I finally got it working. I started it in April and finally got it done in July. I put way more time into it than it was worth, but my work was closed for Covid so I had nothing better to do lol. What I finally found on mine was a bad gate driver IC, IC 704 S21850 surface mount IC on the back side of the board near the heat sink with Q02 and Q03, 30F124's. The IC had it's VCC and Ground pins shorted. I replaced it on my second board too even though it wasn't shorted it looked a little discolored. This IC can easily take a hit when the IGBT's and Fet's blow. I found some on Amazon: https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1 Be sure to check the gate driver resistors on the bottom side of the IGBT's and Fets as well. Most spots have 2 10ohms in parallel for a 5 ohm equivalent resistance and one spot has a higher value. Also measure the large 2W low value through-hole resistors as well. There are some 2.2 ohms and 20 ohms that tend to blow open when those parts short. Other things to look for would be shorted IGBT transistors on the Z-Sustain board or possibly even a shorted Y Buffer. I wouldn't give up on it yet. Those TV's have a beautiful picture when they work. I'm sure with a little more probing, you'll figure it out. Let me know if you have any more questions.

[Sibiemofokeng]

Re: LG 50PJ350 plasma blowing Y-Sustain board

if you have changed gate ics, checked gate resistors and are well,my advice is to use same igbt transistor amperes 200A (30f124)bt now high voltage igbt transistor 30j127,i was getting problem with 42pj350 blowing the igbt transistor,i used 30j instead of 30f and the tv is still playing well.

[angelos]

Hello Siebiemofokeng,
you said that you installed 30J127 IGBT's, where did you find them?
Regards