LG 60ps60

[Tvbob]

Hello all.
I have an 60" LG plasma 60ps60 with a Y sus board EAX55656202.
The set has image retention,artifacts, mal discharge.
Y SUS boards are scarce and expensive for this set.
voltages are as follows
VS-195
Va-67
-vy-178
vsc-140
z bias-104
Can I run it with with a buffer board removed for testing?
Or will it blow the Y sus.

[chrismurphy]

Re: LG 60ps60

Can I run it with with a buffer board removed for testing? NO
Bad joints on Z sus

[Andrew F. Ali]

Re: LG 60ps60

Buffer problem. Remove the UPPER buffer and power on, first.

[Tvbob]

Re: LG 60ps60

I removed the upper buffer first with no result
Also tried set with lower buffer removed no result
Found No bad or (cold) solder connections on the Y sus
Anything I am overlooking?

[Andrew F. Ali]

Re: LG 60ps60

No result means the problem still existed? The Z-sus may still be at fault due to bad caps, etc

[Tvbob]

Re: LG 60ps60

Yes the problem still exist with one of the buffers removed.
My problem is There are not many(EAX55656202) /(EBR55492901) available
Has anybody used "TvPartsToday.com"
There are a few on ebay for $130.00, Don't want to spend that much and find I have a bad panel

[Andrew F. Ali]

Re: LG 60ps60

Plasma panels very rarely go bad. Still looks like a Z-sus Bd. problem to me. Did you measure capacitance and ESR on all the e-caps??

[Tvbob]

Re: LG 60ps60

Yes all caps test good..Not going to look for bad semiconductors.
I found a inexpensive Y sus board in the UK for $60.00 shipped.
Should be here around Nov 9

[Andrew F. Ali]

Re: LG 60ps60

Thanks. Let me know how it goes.

[Tvbob]

Re: LG 60ps60

Well fellow plasma enthusiasts ... I have been through two Y sus boards (used)
All voltages are within specifications. There is a heat sink with two K3453 Field Effect Transistors on the Y sus that gets Hot faster than the rest .
Pic has a few sparkles at turn on that go away after a minute ALL voltages were good..
Last Ysus played about half an hour then a little pop set when dark with images..
Any THOUGHTS

[Unspun01]

Re: LG 60ps60

Well fellow plasma enthusiasts ... I have been through two Y sus boards (used)

TVBOB:

You are mis-reading other people's replies. Users "chrismurphy" and "Andrew F. Ali" have told you to look at Z SUS board, not the Y SUS board.

Z. Not Y.

Z SUS is commonly associated with mal-discharge issues.

Please post photos of your YSUS and ZSUS board.

If you have ZSUS board EAX55656301 / EBR55492601 you may want to check components around the small heatsink Q30, Q31, Q32, large white ceramic resistor R201 (5 ohm or 10 ohm I think?), resistor R209 (1 ohm), zener diode ZD201 (15V or 16V), both 0.22 ohm fusible resistors (red red gold gold), and 6.3A fuse FS102 10A fuse FS100, 2.5A fuse FS101.

You should also check other mosfets or igbts on the other heatsinks.

Not saying any of these are your problem, but I would start there.

If you are certain the problem is on your YSUS board, you should start by looking for shorted mosfets or igbts (on the heatsinks) and post your results. If any of those are bad, their associated gate drivers may also be bad.

[Tvbob]

Re: LG 60ps60

Thanks Unspun01
I revisited my Ysus that I heard Pop
Removed board and removed the dampening tape.
Checked all Major semiconductors for shorts and found NONE.
Reinstalled Ysus and I had a pix for about 5 min and goes very dark.
Turn the set off for about 10/15 min and pix is back on and goes dark again.
I know I heard something pop butt found nothing shorted and all voltages
(vs-194,va-67,-vy-178,vsc-140,Zbias-104) Good
I must be barking up the wrong tree.
I will be looking at the Zsus EBR55492601 Thanks Again

[Unspun01]

Re: LG 60ps60

TVBOB:

Please re-read my previous reply. The panel is priming with a raster and apparent video, so I think the YSUS is working (which is why you did not find any shorts).

Mal-discharge is usually ZSUS problem. Check the parts in the description of my previous reply. See attached image.

Also, you uploaded an image with two 2SK3453 Toshiba MOSFETS. Can you please measure the resistance of that 0.22 ohm fusible resistor in the photo? Looks like it has a pinhole in it and could be suspect. In fact, measure all of the low resistance fusible resistors on YSUS and ZSUS boards.

[Tvbob]

Re: LG 60ps60

You are right again That .22 resistor is open (that is what i heard pop)
My eves are not that good
That resistor also must of opened on the other Ysus boards that I had in there.
I have read LG does not print schematics for there boards.
I have down loaded the Training manual for this set earlier .
I will post my results.
Would a faulty Zsus take out a Ysus ?
THANKS agian

[Unspun01]

Re: LG 60ps60

You are right again That .22 resistor is open (that is what i heard pop)

I'm not sure why that 0.22 ohm resistor would open, but something must have caused it. You're sure you have no shorts on that board?

You could try replacing the resistor, and cross fingers, but if something is bad, it could cause it to open again.

Check the same resistor on your other YSUS board and let us know the result.

Would a faulty Zsus take out a Ysus ?

A Bad ZSUS should not normally take out YSUS, but I suppose anything is possible.

Did you check the components on ZSUS I listed and highlighted in the photo I attached?

[Tvbob]

Re: LG 60ps60

I changed the .22 ohm 1watt (i think) resistor that was open on the Ysus.
I also checked the components that unspub01 suggested along with the other power semiconductors on the Zsus No dead shorts.
The new resistor over heats immediately and still shows a picture with some vertical lines. Also tried Removing one of the buffers (upper or lower) still overheats
Unpluged power cable to Zsus There is no picture but do have raster, and resistor still overheats.
I sent my old Ysus boards to a repair shop in Texas. They do a lot of plasma board repair on ebay, Thy told me they can't service them. I let them keep the old boards.
I am going to oder a board... either a 4th Ysus or Zsus. Chime in please.

[Unspun01]

Re: LG 60ps60

I'm sorry, but the "repair shop" that "specializes" in plasma board repair that "can't fix" your two YSUS boards doesn't sound tight.

I suspect the boards are already repaired and being sold on eBay or will be used for other exchange service repairs. Many of these eBay shops already include return shipping as part of the cost. If you already paid return shipping, I would have requested my old boards back.

There was no damage so substantial that could not be repaired without a few dollars worth of parts. Labor notwithstanding...

In fact, since the main Toshiba 2SK3453 mosfets were not shorted, the problem is probably even cheaper to fix than expected since they do not need to be replaced.

The shop likely knows the issue and can troubleshoot/test right on their bench TV.

The boards you let them keep are worth hundreds of dollars to them for a few dollars in parts.

Can you share which ebay listing you purchased so others can be made aware of this?

On another note:

Your component checks on the ZSUS board seem like the ZSUS is not an issue and can probably rule it out as a cause of your problem.

YSUS continues to be the suspect since the 0.22 ohm fusible resistor gets instantly hot and previously burned. But it is possible YSUS is just a casualty of YDRV buffer issues.

It's possible that one or both of your YDRV buffer boards are damaged. I had a LG 50" plasma with damaged buffer that took out the YSUS. I ended up replacing the YSUS and both YDRV buffers from a cracked screen donor TV.

However, you mentioned vertical lines? this is new. You never mentioned vertical lines before and vertical lines are NOT from YSUS buffers, or YSUS, or ZSUS. That could only be from panel or vertical drivers at bottom of panel... Please share photo of the vertical lines if you have.

[Tvbob]

Re: LG 60ps60

I made all my checks in circuit using my wavetek DM25xt,
I also disconnected the VA cable to the X buffers resistor still gets hot.
The company Is coppell tv repair.In All fairness They Did send me a paypal invoice for return shipping to get my boards back.
(here are the pic's with hot resistor)
Buffers for this set are on the endangered species list...Should I try and turn set on with NO buffers connected to see if resistor get hot?
I have did the static check for shorts using my DVM many times. There are more upper buffers available than the lower .
maybe oder a upper buffer and try it solo to see if resistor gets hot

[Unspun01]

Re: LG 60ps60

Coppell TV repair is well regarded, and has lots of good information on their website and on Youtube - I think he's a pretty stand up guy so I'm sure he did what he could for you.

If he said they are not repairable, he probably meant that they are "not economically" repairable.

Your repair may be outside the common repairs he does for this board so he may have felt there was no money to be made and just decided not to proceed.

[Unspun01]

Re: LG 60ps60

I'm still not convinced your buffer boards are the issue here. A buffer failure usually results in one or more horizontal lines that are dead/black.

A more severe short to one of the buffer ICs would prevent the TV from turning on at all.

However, if your buffer is damaged, but not completely shorted out, it could account for still having an image, and loading down the YSUS board as you are seeing.

We should test the buffer boards before proceeding.

Please provide photos of upper and lower YDRV buffer boards for us to see.