LG 42PT350R clicking problem fixed but still doesn't turn on

[buchman]

Hi,

Replaced a few igbts on ysus and zsus and now the clicking stopped, also the voltages VS and VA are ok. But, when I connect all boardes together it burn out one of the igbt on the ysus.
What I came up to is when I disconnect the ribbon cable between the zsus and the T-CON board, it doesn't burn out the igbt on the ysus.
I know there should be 15V on ysus/zsus/t-con but I am not getting it. All other voltages are ok.

[dick_barton]

Re: LG 42PT350R clicking problem fixed but still doesn't turn on

Are you running it without all the Ysus screws put back in which I think causes problems.

[Andrew F. Ali]

Re: LG 42PT350R clicking problem fixed but still doesn't turn on

are you running it without all the ysus screws put back in which i think causes problems.

+1

[buchman]

Re: LG 42PT350R clicking problem fixed but still doesn't turn on

Are you running it without all the Ysus screws put back in which I think causes problems.

You are serious or it's a joke?

[Andrew F. Ali]

Re: LG 42PT350R clicking problem fixed but still doesn't turn on

You are serious or it's a joke?

Very serious. We don't joke about things like that when someone asks for help.

[buchman]

Re: LG 42PT350R clicking problem fixed but still doesn't turn on

Very serious. We don't joke about things like that when someone asks for help.

How can it make a difference?

[buchman]

Re: LG 42PT350R clicking problem fixed but still doesn't turn on

Didn't help.

[budm]

Re: LG 42PT350R clicking problem fixed but still doesn't turn on

How can it make a difference?

https://www.badcaps.net/forum/showth...ews#post798963

[freakaftr8]

Re: LG 42PT350R clicking problem fixed but still doesn't turn on

These boards have floating grounds. This is not a joke. 1 or 2 screws left out without that particular lug touching a ground point will have disastrous results

[buchman]

Re: LG 42PT350R clicking problem fixed but still doesn't turn on

Probably you were all right. found a few igbts shorted. this weekend I'll solder new ones hopefully it will help.

[ajshoe]

Re: LG 42PT350R clicking problem fixed but still doesn't turn on

what are you using for the IGBTs ?? having a hard time finding good ones - EBAY ones are junk. can these be subbed ??? 30J124 & 30F124. thanks

[buchman]

Re: LG 42PT350R clicking problem fixed but still doesn't turn on

what are you using for the IGBTs ?? having a hard time finding good ones - EBAY ones are junk. can these be subbed ??? 30J124 & 30F124. thanks

That is exactly what I am using. 30J124 as a substitute to the ones that been bad. I buy them from ebay or aliexpress.

[ajshoe]

Re: LG 42PT350R clicking problem fixed but still doesn't turn on

are u using 30J124 for both IGBTs ? that is u replaced 30f124 with 30J124 also ??

[buchman]

Re: LG 42PT350R clicking problem fixed but still doesn't turn on

are u using 30J124 for both IGBTs ? that is u replaced 30f124 with 30J124 also ??

30J124 is a replace for ir7ic....

[ajshoe]

Re: LG 42PT350R clicking problem fixed but still doesn't turn on

sa on some utubes where the 30j124 was being used to replace 30F124

[buchman]

Re: LG 42PT350R clicking problem fixed but still doesn't turn on

sa on some utubes where the 30j124 was being used to replace 30F124

the only difference is that F is for voltages of up to 400V
and J is for up to 600V.

[buchman]

Re: LG 42PT350R clicking problem fixed but still doesn't turn on

My VZBIAS should be 125V and I am getting only 55V.

What could be the reason?

[ajshoe]

Re: LG 42PT350R clicking problem fixed but still doesn't turn on

on my Ysus bd when IGBTs were shorted - also had (2) 2.2 ohm resistors shorted. check those. also check the 15V line on the Ysus board when the set is on from first startup. Mine would go to 18V then go down to 4.1V.

[buchman]

Re: LG 42PT350R clicking problem fixed but still doesn't turn on

also check the 15V line on the Ysus board when the set is on from first startup. Mine would go to 18V then go down to 4.1V.

Mine isn't going to 18V it stays on 4.1V

[ajshoe]

Re: LG 42PT350R clicking problem fixed but still doesn't turn on

your problem is the Ysus - 15V, 15fl, 5fl, are all generated on the Ysus bd. either bad Ysus or bad panel