LG 42PW451ZD - Z-SUS Zener Diode 2 Missing

[Salvatore057]

Hello everybody,
I am new to this forum or at least a new member because I used to read a lot of useful informations since several months.
I am trying to repair on of my TV which the relay is clicking while I try to turn in on.
Thanks to the useful advices I have located the issue on the Z-SUS board and maybe on the Y-SUS on as well (I need to check it later).
The issues I have found on the Z-SUS board were two shorted IGBT 30F124 that I will replace with two 30J124 and also change the IC7 and IC8 on the board. I also noticed a short Zener Diode noted ZD2 attached to one of the 30F124 IGBT.
I have removed this diode but I cannot identify which replacement part I should use.
Could someone help me?
I have read somewhere that using a 20V SOD323 diode should be ok.
Thanks a million for your help.

[buchman]

Re: LG 42PW451ZD - Z-SUS Zener Diode 2 Missing

Hi,
I have the same problem, how did you test the zener diode and the ic's?
I have replaced 2 IGBT's and it didn't help.

[Salvatore057]

Re: LG 42PW451ZD - Z-SUS Zener Diode 2 Missing

Hi,
In order to test the zener diode I removed the 30F124 that was linked to it and then I check for continuity.
Regarding the IC, I did not check it and I am not sure that there is an easy way to check it. But it is recommended to replace the driver IC when replacing an IGBT. If you do not do that, I think that there is a high chance that you will have to replace again the IGBT.

When you say that you replaced both IGBTs and it did not help, is your TV still clicking? Have you only connected the ZSUS w/o the YSUS board?

[buchman]

Re: LG 42PW451ZD - Z-SUS Zener Diode 2 Missing

after I replaced a few IGBT's on the ysus, the tv stopped clicking and even the voltages are fine now. But, if every thing is connected then 2 IGBT's on the ysus are still blowing up UNLESS I disconnect the ribbon cable between the zsus and the t-con board.

[Salvatore057]

Re: LG 42PW451ZD - Z-SUS Zener Diode 2 Missing

Hi,
Are the IGBTs that are getting damaged on the Y-sus the two IRG7IC28U?
Have you replaced the IC drivers? Maybe, they are getting damaged because the IC drivers are bad.
Have you checked solder on the two big coils?

[buchman]

Re: LG 42PW451ZD - Z-SUS Zener Diode 2 Missing

I replaced the IRG7IC28U with 30J124 and yes, they are the two that are getting damaged.
I didn't replace the ic drivers.
checked the soldering and it is fine.

[Salvatore057]

Re: LG 42PW451ZD - Z-SUS Zener Diode 2 Missing

Hi,
Did you finally solve your problem?
I received some parts to fix my TV today but not yet the missing zener diode.
I took a chance in replacing the 30F124 on the ZSUS with some 30J124 leaving the space empty where the zener diode should be (because I think that they have a protection diode inside).
I replaced the YSUS shorted IGBT as well.
I first tested the ZSUS w/o plugging the YSUS and the TV turned ON without picture but I had some sound and the voltages were fine. I then plugged the YSUS to the ZSUS and the TV started to click again without turning ON.
I checked the YSUS and no IGBT were short but the ZSUS is again damaged. I think I will wait until I get the zener diode and I will then also replace the FAN73711 IC drivers.
Hopefully it is not the YSUS than is damaging the ZSUS.

[Salvatore057]

Re: LG 42PW451ZD - Z-SUS Zener Diode 2 Missing

Hello,
I did another test to check if the YSUS board was responsible for the ZSUS being damaged.
I removed the shorted IGBTs from the ZSUS and plugged the ZSUS back in the TV with the YSUS... and then miracle I had a picture on the screen.
So the YSUS seems to be ok.
I have now replaced the FAN73711 from the ZSUS and also replaced the IGBTs. I will wait today to see if I get the diode I ordered. If not I will try to mount a larger Schottky diode just to do a test (SS14).

[buchman]

Re: LG 42PW451ZD - Z-SUS Zener Diode 2 Missing

I am still waiting for my parts. Please let me know if you fixed it and how.
Thanks.

[Salvatore057]

Re: LG 42PW451ZD - Z-SUS Zener Diode 2 Missing

Hi,
Here are some updates on my issue.
I finally managed to get a picture on my TV with both ZSUS and YSUS plugged but the picture is blurred and purple (see pictures attached).
What I did is to replace Q708, Q709, Q703,Q713 and the IC702 on the YSUS and install the 20V Schottky diode that was missing on the ZSUS.
Do someone know why the picture looks like that?
Is it the ZSUS that is still faulty like described by tom66 in his troubleshooting guide?
https://www.badcaps.net/forum/showpo...39&postcount=2

[Salvatore057]

Re: LG 42PW451ZD - Z-SUS Zener Diode 2 Missing

Hi all,
My problem is now solved, I replaced the ZSUS board and the colours are back to normal.
I ordered more parts and will still try to fix my old ZSUS board.
Cheers

[fontypsix]

Re: LG 42PW451ZD - Z-SUS Zener Diode 2 Missing

Hi all,
My problem is now solved, I replaced the ZSUS board and the colours are back to normal.
I ordered more parts and will still try to fix my old ZSUS board.
Cheers

Hi, I have the same problem now. Did you fix your old ZSUS? There are no such expensive parts and I'll try to solve it too.

[chuckjuggernaut]

Re: LG 42PW451ZD - Z-SUS Zener Diode 2 Missing

Hi Ian looking too for the same board…. I need a Part, I think diodes. D23 and D23. Has anybody schematics for it?