Would an LG plasma 60PS60 operate with a bad buffer?

[tucocaps]

Hey all,

I have another more general testing question. Came across this LG plasma, and it has a very cracked screen. However, the set powers on , and the mainboard/sound seems to be working.

I know with brands like Panasonic, if a buffer board get shorted from a screen crack, the set will usually blink error out and not power on. Are other brand sets like LG the same as far as error detection?

Thanks!

[tom66]

Re: Would an LG plasma 60PS60 operate with a bad buffer?

Yes, LG would probably do the same thing except there will not be an error code, it will just not work with Vsc measuring too low.
You should check the buffers for shorts.

[tucocaps]

Re: Would an LG plasma 60PS60 operate with a bad buffer?

Thanks for the quick reply Tom!

I actually have a friend that wants to buy the boards off this set, so the check for shorts would be a good plan.

What is the surest way to check for shorts on the board without damaging them? I remember a video posted here, but I thought it was just for a specific buffer board or brand. Also, do you need a good meter to do this? I still haven't gotten the fluke I was planning to buy earlier this year. Just have a couple of el Cheapo chinese multimeters from harbor freight. These are the kind you get free with coupons.

[tom66]

Re: Would an LG plasma 60PS60 operate with a bad buffer?

This? It works for all plasma buffer boards:
https://www.youtube.com/watch?v=51SZsfH60EY

I demonstrated it on Samsung, but it will work on LG and Panasonic boards too. The theory of operation is identical between them all.

You do really need a meter with a beep. No beep means you have to work much slower, and check each pin for short on 200 ohm range. Just one pin could be shorted. A possible alternative is to wire up an LED with a 9V battery and 220~470 ohm resistor. Attach some probes and you have a poor mans continuity meter .

[tucocaps]

Re: Would an LG plasma 60PS60 operate with a bad buffer?

OK, and there is no chance I could burn one of the chips out using this method?

[tom66]

Re: Would an LG plasma 60PS60 operate with a bad buffer?

With the battery and the resistor? No, the current will be too low to cause harm, you do have to get it the right way around or all will appear shorted.

[sukaht]

Re: Would an LG plasma 60PS60 operate with a bad buffer?

I purchased a broken plasma TV LG 60PS60, it has a 2 inches vertical line. When i open the TV, i found a flex ribbon wire on the bottom of the TV under the vertical line WAS DISCONNECTED. I think this TV has been brought to the repair place and they disconnected this line.
When I tried to connect this ribbon wire to the buffer board, i got the whole section in the middle of the TV (about 2 feed wide) became black.
Do I need to replace the bottom middle buffer board, or i need a new T-CON board?
Thank you for your help.

[sukaht]

Re: Would an LG plasma 60PS60 operate with a bad buffer?

I attached the picture2

Image #2338, #2334, #2335 when the flex wire is disconnected from buffer board (showing 2 inches vertical line)

Image #2333 is when i connected the flex wire (showing the whole middle part of the screen became black).

[mmartell]

Re: Would an LG plasma 60PS60 operate with a bad buffer?

They probably disconnected when trying to find out why the black line was there. The cof for that ribbon may be fried - have a close look at it.

If it's fried it's not repairable.

[sukaht]

Re: Would an LG plasma 60PS60 operate with a bad buffer?

Thank you for your response mmartell.
That's what i am afraid of if COF for that ribbon is fried. But i am still hopping it is not fried.

How do I check the COF ribbon wire is not working anymore?
Can i connect this ribbon wire to the connector next to it? (see the picture below). My plan is to disconnect all the ribbon wires on the bottom, and then shifting the buffer board to the left (the white flex wire from the logic board is long enough for shifting the board to the left).

Or do i need to buy new buffer board or logic board to check that COF ribbon?

[sukaht]

Re: Would an LG plasma 60PS60 operate with a bad buffer?

the COF ribbon looks OK, no burn sign or crack ribbon.
I still believe either the buffer X board in the middle or logic board is causing no picture in the middle and since the vertical lines is divided by 3 sections (left, center, and right) and each section is connected to the logic board.
What do you think? Should I replace the bottom X center buffer board ($22 on eBay) or the logic board ($25 on eBay)
Please help me.

[mmartell]

Re: Would an LG plasma 60PS60 operate with a bad buffer?

I do not know what's safe to test in that area but I would suspect the xc board before the control board. You can rule out the main and control by running the test patterns.

The bottom of the set runs hot - don't run it without whatever heatsinking there is in place or you WILL toast the cof's

[dj01fad]

Re: Would an LG plasma 60PS60 operate with a bad buffer?

hello
I think it's the COF; if you get the whole "buffer" black when you connect the flex wire, then it's the COF. if this would not happen, then you'd have a chance.

[sukaht]

Re: Would an LG plasma 60PS60 operate with a bad buffer?

To satisfy my curiosity since i cant find any burn/fried on that COF ribbon wire, I ordered X Center Buffer board (part#EBR51552301) for $21, and hope for the best.
Probability is 1% but still worth to try. If not I can still sell the parts.

[dj01fad]

Re: Would an LG plasma 60PS60 operate with a bad buffer?

yes, this is true, that 1% is there...
I know the feeing, I had the same problem... twice. let's hope you have more luck than me. in my case it was the cof. in one case it was fried, and in the other case I could not see anything wrong on it.
by the way... I found someone who can fix/replace lcd screens ribbons... is there any little chance that these plasma ribbons can be replaced?

[sukaht]

Re: Would an LG plasma 60PS60 operate with a bad buffer?

I don't think the COF is replaceable, it is bonded to the panel, and it has 256 lines inside this COF ribbon wire.
I found these picture from the service manual LG plasma 50PS60 how to check COF and X Buffer board.

[sukaht]

Re: Would an LG plasma 60PS60 operate with a bad buffer?

I got my X Center buffer board, installed it, and the problem still the same. So I got a damage COF ribbon.
Time to scrap for parts.