LG 50PC3D-UD Powers off 3 blinking lights

[Scougar]

Hi,

I've read a few threads on here about other members having issues with this set, and fixing them. I thought I'd give it a go. A neighbour was throwing this out so I salvaged it.

Issue: Plug-in and it turns on for around 3 seconds. It turns off with 3 blinking lights, no display.

So far:
1) I have checked the fuses and they are all fine.
2) I have unplugged the other boards from the main central motherboard, and the symptom does not change.
3) I have soldered in new capacitors using a kit from ebay (before I realized that badcaps.net sells them!). Symptom remains the same. (Tried number 2 again, and also the same).

Next Actions: I have read that the mosfets and temp sensors are potential failure points, but I don't want to cloud anyone's advice by saying that. How should I proceed with diagnosis? (I have downloaded the manual as in other threads, but it's not making a whole lot of sense to me at present).

Tools I have: Multimeter, Batteries, test lights, wires, soldering iron etc.

Thanks for any help in advance.

[Alastair E]

Re: LG 50PC3D-UD Powers off 3 blinking lights

My guess is--It'll be one of the IPM's is short....

Very common failure on old LG

[tom66]

Re: LG 50PC3D-UD Powers off 3 blinking lights

Agreed. Think it might be a good idea to check Vs and Va on the power board, with and without the Y- and Z-sustains connected (the two large boards either side of the display panel.)

[Scougar]

Re: LG 50PC3D-UD Powers off 3 blinking lights

Thanks gents. Are you able to point me to the test points at all, or a rough guide of what I'm looking to prove? (I'm very much a tinkerer, and am electrically inclined, but not electronically knowledgeable.)

I had thought that it wasn't the IPM's as when disconnecting the power board from the rest, the set did not stay on any longer than previous (which is what I thought it was going to do if it was an IPM ?)

[Scougar]

Re: LG 50PC3D-UD Powers off 3 blinking lights

Ok, so I am going to focus on this again. Add mentioned I had bed replaced the capacitors with no change.

I actually think the ipms are ok as I disconnect the boards and nothing changes. I need guidance where to go next with this.

I would love to find someone local with this tv so I could see if the power board is the fault, and if it is check the screen to see if the tv is worth me buying or trying to repair the board.

The intended use is in the garage for gaming.

[Alastair E]

Re: LG 50PC3D-UD Powers off 3 blinking lights

What are you disconnecting?

IPM's are nearly ALWAYS the fault with these things....

[Scougar]

Re: LG 50PC3D-UD Powers off 3 blinking lights

Disconnecting what I believe to be the Y-sus and the Z-sus, which should allegedly make it power on for longer if they were the issue? (which it doesn't.).

Interestingly... the lights (the row of 4 green led's) isn't always the same even with the same things plugged in.... very odd.


I would be willing to spend $100 on a new board if I new that would fix it, but that's quite a risk.

Hmm.. realized I hadn't uploaded a picture of the back of the unit.. will have to do that later.

[Alastair E]

Re: LG 50PC3D-UD Powers off 3 blinking lights

Hows Vs, Va, when you try and fire it up, with and without Y-SUS connected and same with Z-SUS connected/disconnected?

[Scougar]

Re: LG 50PC3D-UD Powers off 3 blinking lights

Not sure I was doing it right, but I appeared to be getting good voltages. I will look at the service manual and check where to test these again.