32" lg tv flashing??

[ozzy214]

I have a 32" lg tv. I don't know the model number, because the plastic cover disappeared right now. I just acquired 100 tvs from a shop closed down. And things are mess. So I apologize.

But this one is real nice. Amway, all voltages are normal. Tv powers up. Does this flashing screen s thing, like 5x off/on. Then shuts down completely. I have eliminated tcon and invertor shorting out psu, as I unplugged them and still shut down. All voltages stay the same, no dips on any line 12v, 24v, and 5v.

Something is causing psu protect, but I dont know what. I was under the mentality no bulge, then caps are good. But reading here, I find they can be visually good, but still be bad. So Im wondering if it is a cap.

I also do escrap recycling, so have tons of boards I can pull caps to try.

This is a hobby as well as generates some cash since I'm retired. So maybe someone can help me out and give me a idea..I am pulling my hair out on this one..:>

P.s the rest I got are the dreaded 1 year old vizios with bad mainboards, that are far too expensive to fix. So they are getting parted on ebay. I have uploaded pictures so you can see the boards.

[CapLeaker]

Re: 32" lg tv flashing??

What does PSON and BLon signals do? Compare the transformers on the inverter board to each other. If one is more than 3% out, it is bad.

[ozzy214]

Re: 32" lg tv flashing??

pson stays steady 3v till shut down. I forgot reading of blon but stays steady till shutdown as well. Im not sure how to check the transformers on the invertor board, but doesnt really matter. I have had the invertor board disconnected and it still shuts down after a few secs.

[budm]

Re: 32" lg tv flashing??

"pson stays steady 3v till shut down:" That is generated by the main board so if the standby Voltage for running the main board is steady but the PS-ON signal drops off then you have problem on the main board some where.

[ozzy214]

Re: 32" lg tv flashing??

pson is steady at 3v..is it supposed to be higher? im confused

[ozzy214]

Re: 32" lg tv flashing??

Only thing I found is "error" wire reads "3.3v" when it flashes off and goes "ov" when light comes on. What does that mean?

[CapLeaker]

Re: 32" lg tv flashing??

means the inverter detected a problem and shuts off... so either a transformer on the inverter board is bad or a ccfl is drawing too much current.

[ozzy214]

Re: 32" lg tv flashing??

So what happens if you disconnect the inverter? I disconnected and tv still shuts off? I also temp disconnected the error wire and tv still flashes and shuts down.

[CapLeaker]

Re: 32" lg tv flashing??

check the output of the transformers on the inverter board with your ohm meter. if one is more than 3% out than the others, you know you have a bad one.
I am not sure if the error wire supposed to be high or low, when an error is detected.
This gets a bit confusing like this, but it would be better to understand if you write both connectors on a sheet of paper with the corresponding pin outs and measure all voltages on the pins with the tv on and then again, when it shut off due to what ever reason it has and post it here.

[budm]

Re: 32" lg tv flashing??

What is the FULL model number of this LG?
The power supply board looks to be:
LG EAY62308801 ???

http://www.shopjimmy.com/catalogsear.../?q=LG+32LK330

Pictures provided by SHOPJIMMY

[budm]

Re: 32" lg tv flashing??

"But this one is real nice. Amway, all voltages are normal. Tv powers up. Does this flashing screen s thing, like 5x off/on. Then shuts down completely. I have eliminated tcon and invertor shorting out psu, as I unplugged them and still shut down. All voltages stay the same, no dips on any line 12v, 24v, and 5v."
This explanation confused me a little bit, so "All voltages stay the same, no dips on any line 12v, 24v, and 5v" they are still present when you said the unit still goes into shutdown when the T-CON and the Inverter boards are disconnected?

[budm]

Re: 32" lg tv flashing??

I down load the manual for the 32LK330-UB, the ERROR PIN should be LOW for normal operation.
We can verify that by looking up the spec sheet of the LCD panel.
So when you have disconnected the inverter board the ERROR is needed to be GND it to keep it low.

[budm]

Re: 32" lg tv flashing??

If your panel is T315XW03 V.1 (actually it does not matter since the ERROR signal level will have to be the same).
This is what I confirm regarding to the Inverter ERROR signal.
Error signal LOW = NORAML.

[ozzy214]

Re: 32" lg tv flashing??

No voltages stay the same then go go to zero when tv shut down except 5v reference is still there obviously. It doesn't matter if I have the t-con or invertor is disconnected. Voltages stay normal until shutdown. I don't understand by "low", but the error pin reads 3.3v and then 0v fluctuating perfectly with the light flashing on and off. I cant remember right this second, but I believe it was 0v when backlight was off and 3.3v on error when back light was on. Didn't matter if invertor or t con was disconnected, error line kept popping 3.3v off/on. I disconnected the error line out of curiosity and still same flashing, still same 3.3v then ov then 3.3v etc. Only thing I haven't tried is ohming the transformers on the invertor yet. But it seems peculiar that Im getting voltage on the error line even when the invertor is disconnected. Unless the invertor is supposed to backfeed to the main to tell it's on and then I'm getting the error signal because it isnt present. Only thing at this point is the invertor as suggested or possibly main is glitchy. Highly doubt it is a ccfl bulb as panel is nice and bright with no dim spots present anywhere. And highly doubt it's psu as I pulled it and put it on my bench. Activated it and checked it with a dvom, even hooked it to a 12v car bulb for load and it was fine. I didn't check the error line bench testing the psu, but it stayed on without shutting off. I'm not feeling good, getting the flu. But I think I will pull invertor and ohm out the transformers tonight. Thanks for the help.

[budm]

Re: 32" lg tv flashing??

"but the error pin reads 3.3v " <.8VDC = NORMAL, so 3.3V = NOT NORMAL, so for you to disable the error signal you need to GND that pin to keep that line low when you disconnect the inverter board and then see if the main board and the power supply will stay on. When you disconnect the inverter board, the pull up resistor on the main board will pull that ERROR pin HIGH, that is why you need to GND that pin to simulate normal condition, the Inverter board has open Collector transistor that keeps the ERROR line LOW, when the inverter circuit detects problem, the transistor is turned off which will cause the ERROR line to go HIGH.
That ERROR signal tells the main board the condition of the inverter/backlights circuit, when it goes HIGH it tell s the main board it has problem.
BTW, we still do not know the model number of this LG TV.

[ozzy214]

Re: 32" lg tv flashing??

Then the invertor is the issue....was reading 3.3v with the invertor hooked up. Plus I checked the transformers with the dvom and im get 80 on some and 160 on others the 20k scale. So definitely the invertor is fubar. Ok will order a invertor, hooked the error line back up, and post back to see if it is fixed. Found a invertor on ebay for 12 bucks...:> Thanks so much.

[budm]

Re: 32" lg tv flashing??

BTW, it will only take one bad lamp to trigger the ERROR signal, or one bad transformer, etc.

[ozzy214]

Re: 32" lg tv flashing??

Inverter was the fix. Sadly since I had 100 tvs here few weeks ago, I saved the wrong plastic back to it. So now it is "backless" in the shop lol. Thanks for the help in diagnosis.

[CapLeaker]

Re: 32" lg tv flashing??

thanks for the feedback!