LG 50pc1dr - help repairing/diagnosing problem...

[artephius]

Hello.

I picked up an lg 50pc1dr plasma tv that apparently was damaged by a power surge.

When you plug it in the red (standby mode?) led on the front comes on, but if you try to power it up the green light comes on for a couple seconds, then it shuts back off. From reading about this it sounds like some sort of "protection mode" is kicking in and everything I've read seems to point to the power board as the problem.

The person I got it from said they replaced the power board so unless the one they put in was broken as well I assume there must be something else wrong.

So far I've tried unplugging the power cord from the Z board, then the Y board, then both and it still shuts down after a couple seconds.

I wanted to check the output voltages on the power supply board but since it won't stay on I'm not really sure how to go about that.

I also noticed there are 4 surface mount leds on one of the boards that progressively come on as it begins to power up. 3 of them come on but the one labeled D16 never does. Not sure if this means anything or not but I thought it might be worth mentioning.

Any suggestions/advice as to what else I could try?
Thanks!

[artephius]

Re: LG 50pc1dr - help repairing/diagnosing problem...

Update: Just played with it a bit more after posting and discovered something new.

If I unplug connector labeled P802 from the power supply board the tv will power up without shutting off and the light on the front stays green. Nothing shows up on the screen at all though. So it seems that whatever that cable goes to is what is causing the problem. I've attached a picture of the connector that I'm talking about.

Does anyone know what this goes to? It looks like I have to figure out how to take the bottom panel off (where the I/O jacks come out) to see what this goes to. (quite an ordeal from what I can tell...)

[seanc]

Re: LG 50pc1dr - help repairing/diagnosing problem...

That is a picture of your actual board?
It's riddled with bad caps!!

Please list the specifiations of those caps.

Please can you post the specifcations here and take focused pictures of the top of the board and the back.
One good focused picture of both is preferable.

[artephius]

Re: LG 50pc1dr - help repairing/diagnosing problem...

Well the caps that look like the top is popped up on them are all 3300uf 10v and every one of them is popped up like that.

I looked closely and can't find any others that look like that. Not sure if I can take a better picture, that might be the best my camera can do. I'll take the board off and see what I can come up with though.

I know enough to buy new caps and replace them on the board without damaging anything but that's about it so please bear with me

[artephius]

Re: LG 50pc1dr - help repairing/diagnosing problem...

Alright I managed to take some pictures that were a little better. One of the top and bottom. I see 9 bad capacitors - 4 at the lower left, and 5 at the upper left (including the one hiding under the heat sink). I don't see anything else that looks burnt or popped but I'm no expert.

I also found out that board that I have was definitely not the replacement, its the one that got hit by the power surge, the guy actually mistakenly replaced the z_sus board thinking it was the broken one...

[retiredcaps]

Re: LG 50pc1dr - help repairing/diagnosing problem...

Alright I managed to take some pictures that were a little better. One of the top and bottom. I see 9 bad capacitors - 4 at the lower left, and 5 at the upper left (including the one hiding under the heat sink). I don't see anything else that looks burnt or popped but I'm no expert.

If this were my board, I would replace every capacitor, large and small. An equivalent new LG 720p plasma still sells for $700+ CDN so spending $25 USD for caps to replace them all is cheap.

[artephius]

Re: LG 50pc1dr - help repairing/diagnosing problem...

If this were my board, I would replace every capacitor, large and small. An equivalent new LG 720p plasma still sells for $700+ CDN so spending $25 USD for caps to replace them all is cheap.

Yeah that's definitely not a bad idea... I have a friend that knows a LOT more than I do about electronics that's going to take a look at it this week so he should be able to help me pick out the correct replacements for everything. We'll see what happens... I'm hopeful!

[retiredcaps]

Re: LG 50pc1dr - help repairing/diagnosing problem...

I have a friend that knows a LOT more than I do about electronics that's going to take a look at it this week so he should be able to help me pick out the correct replacements for everything.

PCBONEZ's talks about to select caps based on ESR, ripple, etc ...

https://www.badcaps.net/forum/showpo...30&postcount=7

BTW, my $25 USD caps estimate might be high? Caps are usually less than $1 each.

[fireman504]

Re: LG 50pc1dr - help repairing/diagnosing problem...

hey folks I have a lg 50pc1dr with the same problem that you are discussing on here. I do think it is the power supply board...it turns on, clicks a few times and the light stays solid red..if i attempt to power on the tv, it will click and go from red to green a few times and then back to red. i need a board number eax32412301/13 i cant seem to find them anywhere. i can find the /11's does anyone know if they are interchangeable or have any additional ideas

[retiredcaps]

Re: LG 50pc1dr - help repairing/diagnosing problem...

I do think it is the power supply board

Post a picture of your boards like the one shown in post #5. If it has bad caps, it could be an easy fix versus looking for a replacement board. I'm also guessing that new quality low ESR are going to be cheaper than a replacement board.

[PlainBill]

Re: LG 50pc1dr - help repairing/diagnosing problem...

hey folks I have a lg 50pc1dr with the same problem that you are discussing on here. I do think it is the power supply board...it turns on, clicks a few times and the light stays solid red..if i attempt to power on the tv, it will click and go from red to green a few times and then back to red. i need a board number eax32412301/13 i cant seem to find them anywhere. i can find the /11's does anyone know if they are interchangeable or have any additional ideas

Have you followed the recommended troubleshooting procedure for power supply shutdown? Most plasma TVs shut down the power supply if the output voltages are not within specs within a few seconds of turning on the TV. Also, as retiredcaps suggested, are there any signs of bad caps?

PlainBill

[wjnparkmnsmn]

Re: LG 50pc1dr - help repairing/diagnosing problem...

where can I get new capacitors for my board? Same spec's as above (50pc1dr power board).... I haven't open the tv yet but from everything I've read the problem will be the same as above. Do the caps plug in or is there soldering involved? thanks for all responses.

[retiredcaps]

Re: LG 50pc1dr - help repairing/diagnosing problem...

where can I get new capacitors for my board?

Do the caps plug in or is there soldering involved?

1) The answer is literally above your original post.

2) Caps need to be soldered in.

[bevzon]

Re: LG 50pc1dr - help repairing/diagnosing problem...

i have the same problem with my lg42pc3d. but 10v caps not popped up, some one on the web suggested just replace all 10 of them. seems like good idea now after seeing your pix. i found pack of 10 pcs 3300mf10v for 4.20$ good deal

[artephius]

Re: LG 50pc1dr - help repairing/diagnosing problem...

Mine still didn't work after replacing the caps and a varistor that looked bad so I ended up just getting this replacement board: http://www.encompassparts.com/products/?ZENEAY32957901

It worked! But $10 on parts sure beats $160 for a new board so it's worth a try.

[gar14]

Re: LG 50pc1dr - help repairing/diagnosing problem...

Artephius,

I am about to embark on a similar repair. Do you have any words of wisdom after having gone through the process? I will take even the most basic help, such as what to remove and not remove. Thanks.

[tom66]

Re: LG 50pc1dr - help repairing/diagnosing problem...

I am in the process of repairing one of these sets, which had bad caps initially. However, replacing them doesn't seem to have fixed it. I have a theory that the bad caps have killed the main board in some way, so I'm in the process of replacing those parts.

[bobster99]

Re: LG 50pc1dr - help repairing/diagnosing problem...

I ended up with a LG 50PC1DR. At first the unit would turn on, have a couple of 1 pixel vertical lines and buzz like a bad razor.

After about 5 minutes the buzzing would go away and the unit would work great. The lines disappeared and everything was fine. After using it for 3 days without a buzz or a problem I was convinced that it was fine and I got a Cable Card and was all set.

Then last night it suddenly stopped working, no buzzing, blank screen, it just won't turn on. The Led in the front is on but the remote nor the button will do anything.

My best guess is that the power board has died, I haven't checked for bad caps yet nor have I even located which board. Is there a parts diagram out there for this unit and how do I prove the power supply board or possibly something else is the problem?

[tom66]

Re: LG 50pc1dr - help repairing/diagnosing problem...

I ended up with a LG 50PC1DR. At first the unit would turn on, have a couple of 1 pixel vertical lines and buzz like a bad razor.

After about 5 minutes the buzzing would go away and the unit would work great. The lines disappeared and everything was fine. After using it for 3 days without a buzz or a problem I was convinced that it was fine and I got a Cable Card and was all set.

Then last night it suddenly stopped working, no buzzing, blank screen, it just won't turn on. The Led in the front is on but the remote nor the button will do anything.

My best guess is that the power board has died, I haven't checked for bad caps yet nor have I even located which board. Is there a parts diagram out there for this unit and how do I prove the power supply board or possibly something else is the problem?

Open the TV up; you'll easily be able to see bulged caps.

[bobster99]

Re: LG 50pc1dr - help repairing/diagnosing problem...

Yep... bulged caps everywhere. It looks like there are maybe 2 or 3 different sized caps that are bad.

Did LG just use substandard quality or is this just what happens...

Really what I am asking is... should I replace all the caps or just the ones that are popped?

There are somthing like 21 caps on the board and maybe 8 or so that look bad.
Do I replace the 8 or all of them?