LG Plasma won't turn on after resoldering cracked joints

[TVTinkerer]

I have an LG 60" plasma that is about 7-8 years old. A year or so ago it started getting some discoloration on the top part of the screen, but the picture still showed up and looked good on the rest of the screen and it always turned on/off just fine. Due to the discoloration I stopped using the TV, and it just sat in another room for about a year. I decided to try fixing it this past weekend so I did some reading online and learned that there are typically some solder joints on the YSUS and ZSUS boards that can crack and need to be reflowed. So I took the back off the TV (forgot to test it again before doing that, unfortunately) and pulled out the boards, and sure enough there were some cracked joints on the back. So I reflowed all the joints, but now the TV won't turn back on. When I try to turn it on I get a high pitched buzzing/ringing sound coming from the ZSUS board and then it shuts back off. When I turn it out without the ZSUS board plugged in then it stays on, but of course there is no picture.

Is it possible that i damaged something while reflowing those solder points, like if I used the solder iron at too high of a temp or something? Here's a video showing what's happening when I turn it on.

https://photos.app.goo.gl/8z6SQQkpRSCLRF412

[freakaftr8]

Re: LG Plasma won't turn on after resoldering cracked joints

Ringing buzzing sounds usually are inductor coils on the Z sustain board.

Did you put all the screws back in and tight on the Z board before you powered up If you have one or more screws missing, it will short mosfets on the Z sustain board

[TVTinkerer]

Re: LG Plasma won't turn on after resoldering cracked joints

Well shit. I did try to power it up before putting all the screws back in, and then when it made that sound and shut off a few times that's when I put all the screws back in and tried again with the same result. Did I maybe short out some mosfets by not putting the screws back in before powering it back on the first time?

[tvtimmy]

Re: LG Plasma won't turn on after resoldering cracked joints

In a word........yup.
What is the tv model number and the board number? You may only have to replace 3 IBGTs on the black heatsink.

[TVTinkerer]

Re: LG Plasma won't turn on after resoldering cracked joints

TV Model: LG 60PZ950
Board: EAX64232101

Is there a way to test them with a multimeter to see if they're bad?

[freakaftr8]

Re: LG Plasma won't turn on after resoldering cracked joints

Yes. Ohm setting. Black to pin 2. Red to pin 1 then 3. If beep or low ohms they're bad

[TVTinkerer]

Re: LG Plasma won't turn on after resoldering cracked joints

Thanks, I'll give it a try.

[TVTinkerer]

Re: LG Plasma won't turn on after resoldering cracked joints

Oops, double post.

[TVTinkerer]

Re: LG Plasma won't turn on after resoldering cracked joints

I haven't tested the mosfets on the ZSUS board yet, but now you have me curious about the YSUS board. Since I didn't put the screws back into that board either before testing, do you think that one has blown mosfets too? It doesn't cause the TV to turn off like the ZSUS board does, but is there chance they're still damaged?

Also, I watched some videos online about how to test mosfets, and they all say you shouldn't have it touching anything else when tested. Does that mean I need to remove them from the board to test them?

So pissed off at myself for trying to save 2 minutes and test the board before putting all the screws back in.

[freakaftr8]

Re: LG Plasma won't turn on after resoldering cracked joints

Maybe the y board is ok. I'd check mosfets just to be sure though. It's a simple mistake. Ask me how I know =-) Not a lot of boards out there that use floating grounds. I know LG and Panasonic do.

[Nick's Tvs]

Re: LG Plasma won't turn on after resoldering cracked joints

Your Y sus is most likely fine however probably also has cracked solder joints on the inductors (the copper looking coils) so those are always a good idea to reflow. However you most definitely will have a blown fuse as well as shorted transistors and possibly blown resistors near one of the rows of bad transistors.
There are kits out there for this board, but most have way more than you need.
Like I said most often just the transistors, the fuse and 2 resistors is all you need.

If you can't get it fixed or figured out, here is a link to a repair service

https://www.nickstvs.com/store/p612/...Repair-Service

Good luck

[TVTinkerer]

Re: LG Plasma won't turn on after resoldering cracked joints

I did take the YSUS board off too though, and also reflowed joints on there, and hooked it back up without installing the grounding screws.

[TVTinkerer]

Re: LG Plasma won't turn on after resoldering cracked joints

Your Y sus is most likely fine however probably also has cracked solder joints on the inductors (the copper looking coils) so those are always a good idea to reflow. However you most definitely will have a blown fuse as well as shorted transistors and possibly blown resistors near one of the rows of bad transistors.
There are kits out there for this board, but most have way more than you need.
Like I said most often just the transistors, the fuse and 2 resistors is all you need.

If you can't get it fixed or figured out, here is a link to a repair service

https://www.nickstvs.com/store/p612/...Repair-Service

Good luck

LOL. I've actually had a tab with that exact page open in by browser for the last few days. Been debating between trying to replace the Mosfets myself, or just pay the $55 and have you do them.

I'm actually not too far from you either, I'm in south Chandler near I-10 & Riggs.

[dokymobil]

Re: LG Plasma won't turn on after resoldering cracked joints

Hello everyone ! i do the same mistake on my 60pg45 but im just don't put back all the screws after the capacitors changed on the sub power board.
there is the result...

[Nick's Tvs]

Re: LG Plasma won't turn on after resoldering cracked joints

If you have a soldering iron and the ability to do it, I would say go for it, it really isn't all that hard, it just takes time and patience.