I think I fried a good ZSUS board on an LG plasma

[goldbird78]

Hi All, I have read a lot here but First time posting. I could use some help....To make a long story short, I have/had two LG 50PS60 TV'S and one died yesterday so to diagnose the problem I was swapping out boards and found out the hard way that ZSUS boards must be fully mounted with all screws to be grounded properly. I swapped the ZSUS board from the good TV and put it into the broken TV and all worked well so I removed it and put it back into the original TV that had no issues but stupidly I just put a couple screws in to start it up and test to make sure all cables are good, TV came on for 10 seconds and "snap" screen went dark with a redish background. The fuse did blow on the board and I have replaced it but now the TV will turn on for about 3 seconds and shut off. I am assuming I popped a resister or diode ??? Have I totally fried the board or is there something I can replace to repair the board. Thanks in advance.

[tvtimmy]

Re: I think I fried a good ZSUS board on an LG plasma

They are very cheap on ebay. Make sure you get the correct one, as there are about 5 versions for this tv. I think it would be cheaper to just replace the board(s) than to buy all the things you blew up.allways put all screws back in everything!!!

[tom66]

Re: I think I fried a good ZSUS board on an LG plasma

Yes unfortunately you have damaged the board without installing all of the screws. But the question is whether it is worth repairing or not. If you do not have the experience and knowledge to repair a Z-sustain board it is probably not worth doing especially if you can get a new board for relatively little as tvtimmy says... Chalk it down to a lesson learned I guess...

[goldbird78]

Re: I think I fried a good ZSUS board on an LG plasma

always put all screws back in everything!!!

Yeah, no kidding I did purchase one one E-Bay this morning. Except for the fuse blown there is no signs of damage or burn marks on the board or any components. Being a technician in another trade I would like to try to figure out what else popped. I would hate it to be just one or two diodes or transistors ?? With the fuse blown the TV will stay on with a very dark red pixelated image, with the fuse replaced it shuts off after 3 seconds. Anyone have idea's ? I know it may be a time waster but for me its more for learning. Thx

[goldbird78]

Re: I think I fried a good ZSUS board on an LG plasma

Yes unfortunately you have damaged the board without installing all of the screws. But the question is whether it is worth repairing or not. If you do not have the experience and knowledge to repair a Z-sustain board it is probably not worth doing especially if you can get a new board for relatively little as tvtimmy says... Chalk it down to a lesson learned I guess...

I have purchased another board but still wouldn't mind taking a stab at repairing the board if someone could point me in the right direction. I am very good with a meter and soldering iron.

[goldbird78]

Re: I think I fried a good ZSUS board on an LG plasma

I do have a couple LG boards that I can scavenge parts from if needed....And no I did not blow these one up...Lol

[tvtimmy]

Re: I think I fried a good ZSUS board on an LG plasma

Post a pic of the boards installed in the back of your tv. I want to see what is what and how they are connected.

[goldbird78]

Re: I think I fried a good ZSUS board on an LG plasma

Post a pic of the boards installed in the back of your tv. I want to see what is what and how they are connected.

will post it tomorrow, I have the board out and the tv put away right now.

[goldbird78]

Re: I think I fried a good ZSUS board on an LG plasma

I m trying to post a JPG pic when it was in the TV but it keeps telling me incorrect file extension.

[goldbird78]

Re: I think I fried a good ZSUS board on an LG plasma

can anyone point me in the right direction on what might have popped on the board ? Thx

[goldbird78]

Re: I think I fried a good ZSUS board on an LG plasma

here is a picture of the board.

[tom66]

Re: I think I fried a good ZSUS board on an LG plasma

You would need to check all of the IGBTs (transistors) on the heatsinks to see if any are shorted.
If they are shorted they will need replacing. You can remove them from the circuit to confirm.

[goldbird78]

Re: I think I fried a good ZSUS board on an LG plasma

You would need to check all of the IGBTs (transistors) on the heatsinks to see if any are shorted.
If they are shorted they will need replacing. You can remove them from the circuit to confirm.

Thanks for the reply. So I am assuming if I get 100% continuity through each pin with no resistance they are shorted ? any particular pin sequence or just check all 3 in any order ?

And are you talking about all the 45f122, rf2001 & 20nf20 transistors on the heat sinks ?

[tom66]

Re: I think I fried a good ZSUS board on an LG plasma

Yes I'm talking about 45F122 and 20NF20. RF2001 does not need testing - it is a fast diode and unlikely to fail.

You should check all three combinations and they should all appear open circuit. A low value in any direction indicates a fault (confirm by removing the device and checking out of circuit.)

It is common for only a few parts to be bad, but when tested in circuit many can look bad.

[goldbird78]

Re: I think I fried a good ZSUS board on an LG plasma

Yes I'm talking about 45F122 and 20NF20. RF2001 does not need testing - it is a fast diode and unlikely to fail.

You should check all three combinations and they should all appear open circuit. A low value in any direction indicates a fault (confirm by removing the device and checking out of circuit.)

It is common for only a few parts to be bad, but when tested in circuit many can look bad.

Thanks so much for your help...Is there any need to check the big or small capacitors ? None look swollen or damaged

[tvtimmy]

Re: I think I fried a good ZSUS board on an LG plasma

Not really.

[thumper69]

Re: I think I fried a good ZSUS board on an LG plasma

do all the screws in also apply to testing of power supply board.

[tvtimmy]

Re: I think I fried a good ZSUS board on an LG plasma

You wouldnt drive your car with only 3 wheels on it, would you?

[goldbird78]

Re: I think I fried a good ZSUS board on an LG plasma

Yes, valuable lesson learned.....Moving forward all screws will go in all components when testing.

do all the screws in also apply to testing of power supply board.

[tom66]

Re: I think I fried a good ZSUS board on an LG plasma

You can only omit screws if you're willing to trace through the board and figure out which ones are really necessary. There are some boards also that use the heatsinks to pass the ground plane through. I have learned that lesson too when trying to run a board without the heatsink. Thankfully I had a bulb in place so it didn't blow up anything but it certainly didn't work.