42PT353 ZSUS faulty or the panel???

**ReeceyBurger123** · 03-22-2016, 06:46 AM

Re: 42PT353 ZSUS faulty or the panel???

What are the symptoms of the failure first dark red hazy image ? Rarely do the Plasma panels fail unless they get cracked.

**hannesmen** · 03-22-2016, 08:29 AM

Re: 42PT353 ZSUS faulty or the panel???

Well, with the first faulty Z board the image simply stayed black. After a few seconds I could hear a sort of a fizzling (not a clicking) and then the red light turned on again. Obviously, the TV recognizes a problem and starts the protection mode why the TV goes back into the stand-by mode.
I could locate the fizzling on the Z-sus board. I disassembled and found that it is faulty why I bought a new one.

I assembled the new Z board. For a second I could see a snowing image and they it became black again. Now the TV behaves similar as with the Z board before. It stays black and after a few seconds goes back into the stand-by mode. I checked the Z board again and it is faulty again.

Unfortunately, I did immediately connect the Y board and didn’t check if it works only with the Z board and without the Y board.
So, if the panel rarely breaks. Probably the Y board causes the break of the Z board? What is the best way to check it? Resistance between Vs and Gnd Show around 0,350 MOhms?

Regards
Hannesmen

**hannesmen** · 03-23-2016, 03:44 AM

Re: 42PT353 ZSUS faulty or the panel???

Is it possible that shorts on a panel cause the zsus board to break? I found some faulty diodes and igbts (30F124) and the part RD2004 where I'm not sure if it is a diode or transistor. And this parts failed already a second time now?

Btw, I should mention that before the TV completely broke sometimes after I turned off the TV (when it should go to Stand-by) the image became somehow bright and the TV did not responded any more. I had to plug off the TV for some time until I could start it again.

Thanks for any feedback.

**vinceroger69** · 03-23-2016, 04:22 AM

Re: 42PT353 ZSUS faulty or the panel???

A search suggests a RD2004 is a Switching Diode.

**victor_cj** · 03-23-2016, 04:45 AM

Re: 42PT353 ZSUS faulty or the panel???

Check the signals from CTRL board with a oscilloscope, or replace this board.

**hannesmen** · 03-23-2016, 05:42 AM

Re: 42PT353 ZSUS faulty or the panel???

Thanks for your feedback men!

RD2004: I could find a lot of datasheets for RD2004JN, RD2004JS-SB or RD2004LN. But no one dedicated only to RD2004. I have attached pic of the part.

Unfortunately, I have don't have a oscilloscope. But can the CTRL board cause the ZSUS to break in a way that the igbt's get damaged?

Attached Files

**aaronwt6** · 03-23-2016, 05:53 AM

Re: 42PT353 ZSUS faulty or the panel???

Did you have all of the screws firmly in place when you turned it on? If you tried to check it with only some of the screws in place, that can cause a failure.

**hannesmen** · 03-23-2016, 06:20 AM

Re: 42PT353 ZSUS faulty or the panel???

Honestly, I have to say that I didn't have used one screw to fix it as I turned it on with the new Z board

Do you think this is the reason and probably the TV would work with a new Z board having all screws firmly tighten?

But somehow the same parts failed as those which are also faulty on the old Z board (which was always screwed before it failed)?

**ReeceyBurger123** · 03-23-2016, 06:45 AM

Re: 42PT353 ZSUS faulty or the panel???

That's why it failed then, sustain boards use local ground for a good reason ! You probably shorted out the fets by not screwing it all down properly. Also have you checked the Ysus for S/C ?

**hannesmen** · 03-23-2016, 07:08 AM

Re: 42PT353 ZSUS faulty or the panel???

Ahhh, if this is true I could hit myself.

The YSUS board is connected from the Z board. I checked the YSUS and measured a high resistance value (0,350 MOhms) between Vs and Gnd. And most of the IGBTs and diodes which I measured look good. So I have still the assumption that the Y board is good. (But I'm not sure of anything anymore.)

But I can't understand why would exactly the same parts fail only because of missing screws? That is why I thought that maybe a faulty panel caused the same parts to break again? Because I have no clue what else could damage the parts on the Z board?

**ReeceyBurger123** · 03-23-2016, 07:19 AM

Re: 42PT353 ZSUS faulty or the panel???

Even if the panel was bad it would not kill the sus boards, it would only kill them if it was cracked. The missing screws can do the same. Try a new board mate. Panel failure is very very rare.

**hannesmen** · 03-24-2016, 03:26 AM

Re: 42PT353 ZSUS faulty or the panel???

The Mosfets AUK SMK0825 look good to me. I can measure for all Mosfets a working body diode.

Btw, does anyone knows what could cause to break the IGBTs and diodes on the original Z board?

Before I do buy and spend money for a new Z board again I would like to try to replace the faulty parts on it (at least those I discover).
If I would get the parts easy it would be worth a try. But after a first search with Google I'm not really confident to get them easy.

So far I found:
2x IGBT 30F124
2x 3-Pin Diode RD2004 (I can't find exactly this p/n but RD2004LN or RD2004JN)
2x Diode has a 88 on the package: Acc. forum should be RF101L4S.

I was looking for a technical document with parts list but failed to find.
Does anyone can help with a tech doc for LG42PT353?

**hannesmen** · 03-24-2016, 08:30 AM

Re: 42PT353 ZSUS faulty or the panel???

I'm one step further

I wanted to desolder RD2004 but failed ... so I took a cutter as I thought it is bad anyway. But to my surprise the diode is working out of circuit

.
Anyhow, I need a new as the legs are too short now.

Did the same for the two IGBTs 30F124. And these are bad (lucky me).

I have to ask again, is it really possible that that the missing screws caused to fail the IGBT???

**ReeceyBurger123** · 03-24-2016, 08:42 AM

Re: 42PT353 ZSUS faulty or the panel???

Yeah it can cause that as the would be grounded.