50" LG Y-sustain IPM modules

[dkneyle]

Re: 50" LG Y-sustain IPM modules

(End of the story.) I removed the ribbon cable on the lower buffer board, gently brushed it and the connector with some metho spirits (alcohol), reassembled. ALL GOOD! Giving it a good heat soaking at the moment to see that all holds up well. Anyone who comes to this thread looking for guidance with a similar problem, just check those 10 ohm resistors on the Z-Sus baord. I would never have known about those except for the tip off. I replaced with conventional 10ohm 1/2 watt resistors; there's plenty of room to do so.

[dkneyle]

Re: 50" LG Y-sustain IPM modules

So, I changed the Y-Sus board over. I also found that two 10 ohm resistors on the Z-Sus board had gone open circuit and they were replaced. (Tks tw2005 for that hint.) The plasma fired up all OK. After about 10 minutes I noticed a horizontal black line towards the bottom of the screen. I don't think it was there when I first got the TV going? I did take out the y-driver boards to check for shorts, so I'm hoping it's just a cable not pushed home, or some dust. I will report back! The IPMs seem to be running warm but not hot. The voltages are spot on - I didn't need to reset them. We've gone from a completely dead set to one that runs except for a minor screen blemish which I'm confident I'll get on top of.

[tw2005]

Re: 50" LG Y-sustain IPM modules

not sure if this doc helps but paragrah 2. both modules would need testing.

see how you go. you'd have to go by the pin description, i think the photo is a different module but a picture is shown of the 50X3 and they're the same modules paired on both the y and z

[tw2005]

Re: 50" LG Y-sustain IPM modules

You are a wealth of knowledge. I looked at those resistors. No sign of stress. I put my meter across them: I get a reading of 40K, not 10 ohms as expected. From your experience, when they blow, do they usually look physically damaged?

I was assuming that the Y-Sus was the main culprit because if I removed Z-Sus from the power daisy chain the power supply still wouldn't hold up.

So, here's the question for you based upon your experience. If I changeout the Y-Sus board with a working board, and replace those resistors on the Z-Sus board, will that generally get things going? Or is the Z-Sus board also likely to need a complete changeout??

I don't have that much knowledge on these but there would be a way of confirming the IPMs on the Z are bad or not using a meter but I don't know the procedure. Maybe try googling test lg ipm or copellTV might have a blog or info on it.

I'd expect burning or maybe a pinhole in the resistors but being such a low resistance it is conceiveable they are open or gone high.

On the one I had which was an aborted repair by someone else they burnt making us think the ZSUS was bad but with that one it turned out to be ok after replacing those and repairing the y.

I think they may be in parallel those resistors too but unsure so 5 ohms may be expected there.

One thing is for sure you should see at least theresistor value or lower there, definitely not higher.

too long ago for my memory now, that's all I got for you.

Someone else may have better info for you.

[dkneyle]

Re: 50" LG Y-sustain IPM modules

The ZSUS get power from the YSUS so a bit of an assumption it's good too.

Also I've seen a bad ysus cause R9,R91 10ohm 0.5W SMD resistors to burn up on the ZSUS. Bottom left near a bank of capacitors.

Last one of these i fixed I sold for about $180 18 months ago.

You are a wealth of knowledge. I looked at those resistors. No sign of stress. I put my meter across them: I get a reading of 40K, not 10 ohms as expected. From your experience, when they blow, do they usually look physically damaged?

I was assuming that the Y-Sus was the main culprit because if I removed Z-Sus from the power daisy chain the power supply still wouldn't hold up.

So, here's the question for you based upon your experience. If I changeout the Y-Sus board with a working board, and replace those resistors on the Z-Sus board, will that generally get things going? Or is the Z-Sus board also likely to need a complete changeout??

[tw2005]

Re: 50" LG Y-sustain IPM modules

I have an LG 50PX5D with the symptoms that very much meet those of this thread. That is: Switch power on, power supply tries to start, fans come on, after about 5 seconds drops back into standby. Disconnected supply to Y-Sus board and the power supply stays up. Reconnected the Y-Sus supply and disconnected the supply to the Z-Sus board - power supply drops back into standby. Therefore, along the lines of this thread I assume probably the IPM chip/s have failed on the Y-Sus board. However the fuses are in-tact. No signs of any visible damage such as bulging caps. (I have also replaced the power supply so I'm confident it is OK.) Because I don't have the gear I wasn't about to changeover the IPM modules, but planned on buying a secondhand Y-Sus board. However before investing >$120 I wanted to check what others thought from my described symptoms and self diagnosis.

The ZSUS get power from the YSUS so a bit of an assumption it's good too.

Also I've seen a bad ysus cause R9,R91 10ohm 0.5W SMD resistors to burn up on the ZSUS. Bottom left near a bank of capacitors.

Last one of these i fixed I sold for about $180 18 months ago.

[dkneyle]

Re: 50" LG Y-sustain IPM modules

I was going to replace mine but the work involved was a pain. So I got lucky and bought a used ysus board on Ebay for $50 shipped.

And I assume that got you going again??

[dcapper]

Re: 50" LG Y-sustain IPM modules

I was going to replace mine but the work involved was a pain. So I got lucky and bought a used ysus board on Ebay for $50 shipped.

[dkneyle]

Re: 50" LG Y-sustain IPM modules

I have an LG 50PX5D with the symptoms that very much meet those of this thread. That is: Switch power on, power supply tries to start, fans come on, after about 5 seconds drops back into standby. Disconnected supply to Y-Sus board and the power supply stays up. Reconnected the Y-Sus supply and disconnected the supply to the Z-Sus board - power supply drops back into standby. Therefore, along the lines of this thread I assume probably the IPM chip/s have failed on the Y-Sus board. However the fuses are in-tact. No signs of any visible damage such as bulging caps. (I have also replaced the power supply so I'm confident it is OK.) Because I don't have the gear I wasn't about to changeover the IPM modules, but planned on buying a secondhand Y-Sus board. However before investing >$120 I wanted to check what others thought from my described symptoms and self diagnosis.

[stupidcomputerrepair]

Re: 50" LG Y-sustain IPM modules

I forgot to note, there is an 8-pin PWM control IC that drives that 18v regulator. they are all within the same spot of the 18V regulator.

What i do is have both IPMs removed, have the bare board sitting on the bench, and I hook a lab power supply up to the 5V rail, set it to 5V, and test my 18V output.

this is the safest way to test the output of the regulator, without having all these rampid high voltages around while testing in the set, risking probe slippage and blowing shit up like i normally do.

I have the pictures, I just have to get them off of the camera. besides, I rebuilt the ER IPM and she held up just beautiful. its the SUS IPM that blew, but i stuck a regular unrebuilt known good ER IPM in its place to eliminate that as a factor, before it blew out, and it blew out anyway.

you never posted the pictures of what you replaced in order to rebuild the ipm, and a part list for what you used. id love to be able to see those pics and the list. thanks

[stupidcomputerrepair]

Re: 50" LG Y-sustain IPM modules

I miswrote , I realized I had replaced the SUS IPM, not the er, I realized as I was checking all my Voltages and it was marked on the YSUS PCB.

My voltages are as follows:
Outputs from the PSU I measured on the PSU connector that goes to my YSUS, Va=63.2vdc, Vs=195. Then on Connector P5 ON MY YSUS board I probed and got 6.7vdc showing where its labled 5v.

Grounds i probed accidentally but most show voltage when set is running, that must be usual and i just dont know it.
BTW: no overheating IPMs, in fact it seems teh YSUS ones barley get warm

Anyone have some input?

[stupidcomputerrepair]

Re: 50" LG Y-sustain IPM modules

The manual in the link I posted above shows a power distribution schematic of the boards. I have the .pdf file downloaded and saved.

Hi , Laptop Stevie here, I have a z50px2d. Got free. Went on , has sound , no pic. Felt all IPMS and found Ysus lower IPM(ER IPM) was cold. Removed it by loosing heat-sink with pliers till heatsink very loose then i could slip under some dikes and snip off all legs and take it out, I found blown damage on underside. Got replacement Used but "Well tested" off ebay j015b. Didnt have hot enough iron so i snipped the old legs still in Yboard to the same height and installed my replacement piggyback. This only ended up that the replacement was 1/4 inch higher off the yboard than stock, I was happy with that and reassembled the set.

Fire it up and same thing. no picture. bummer

removed the Drivers upper and lower and found no damage to the chips , only did close visual inspection.

When i got the set i checked all voltages on the YSUS that were labled to see if all were ok, only low voltage 5v and 18 , i recall all were ok. Didn't know there is a sticker telling v's voltages so today when i get home ill recheck ll voltages including the v's. All caps in the set appear fine.

Im an old Auto Mechanic, who turned laptop repairman, Im not an Electronic Tech, im trying to teach myself Tv repair. Out of about 15 Lcd's Ive gotten 10 working, Ive done mostly Caps and Boards. I do not know if i can check SM Diodes in the circuit, my only current knowledge is to check continuity in both directions, dont know how to test MOSFETS either, just printed out some sheets to follow at home.

What do you guys think tho? Any hints?

thanks

Laptop Stevie!

[father_fixit]

Re: 50" LG Y-sustain IPM modules

By the way I think the thing that killed my YSUS in the first place was the top two caps in the bank of orange caps next to the top heat sink. It looks like they got too hot and bled out some waxy material that dripped down the board. The first thing I did to this set was swap those two caps from a cannibalized set, but didn't help, so I disregarded the issue and went on to other components. It wasn't till I tried to fire up the set I put the leakers into, and watched an IPM blow that I realized they may have started the cascade of failing components. My theory is that the heatsinks got very hot because of inadequate cooling, caused leakage in the caps directly adjacent to it, then caps destroyed the IPM and on to the FETs. After the repair I installed cooling fans in the back cover right above the SUS boards to blow heat out. A year and a half later, still running great (and cool).

[SpecialK]

Re: 50" LG Y-sustain IPM modules

Hi,
I just received a J015B IPM I bought from Utsource; they offered the module at a low price and their handling time was short. So I'm pleased with their service.

But... I installed the new IPM on my Z_SUS board today, and although the set works again, the IPM runs very very hot. I had the set running for a few minutes, and after that the IPM was already too hot to touch. The other modules (J016B and the modules on the Y_SUS) remain cold or become slighly warm. I'm pretty sure if I leave the set on, the J015B will pop again in less than 15 minutes. I didn't replace the J016B.

18V on the Z_SUS measures 18,2V; Z_BIAS measures 94,5V, I'll adjust that later. Could that slightly higher Z_BIAS voltage be the reason why this IPM runs so hot? Or should I look elsewhere?

The set is an LG 50PX4R-ZB.

[fatahab]

Re: 50" LG Y-sustain IPM modules

@Omnifix
I got quotes for ysus IPMs from "utsource", but have not tried to buy them yet. I was going to try rebuild them like mbates and the Russians in this thread
In case your trying to match that specific revision I think i read on CoppelTv's blog that the series are interchangable as long as you pair it with an ER IPM in the same series, so you could get J015C or E with a matching J016C or E.

I picked up three of these LG 50x3 panels the last few months, a Vizio p50hdm, LG 50px5d, and a toshiba 50hp66. I was able to get one set running just by swapping ysus boards. Now I'd like to get another full set working at least for spare parts, as I'm counting on those IPM's to fail. Since I had two failed ysus boards i picked the worse one to try rebuild so if I gave up i could still send the better board to CoppellTV for rebuilding. After trying double soldering irons and a cheap soldering gun, I was able to desolder the IPM's with a heavy 1/2" 100watt soldering iron meant for plumbing or something.

[Omnifix]

Re: 50" LG Y-sustain IPM modules

I know this thread is dead but I am going to do my best to get something alive on it, I have a z50px2d 50" Zenith I just picked up and I need to find the YPPD-JO15B IPM to replace the bad ones. I get the runaround from the chinese trader sites and ebay seems to have forgotten about them, as far as the removal/replacement method I have had good luck with a dremel tool and metal cutting blad to cut the pins off right next to the chip and then clean/flux and resolder the new chip directly to the old pins, it makes for easier removal and replacement since the pins are far enough up on the board to reach with solder braid on the surface, as for the heat sinks if there arent any hold to access the head of the screw I drill out the threads on the heatsink and use long through bolts with lock washers and nuts on top so you can hold the head easily with an end wrench and tighten from the top with a deep socket.

[father_fixit]

Re: 50" LG Y-sustain IPM modules

I had 16.3v on the YSUS before and after replacing the bad IPMs. I was told by a good source that that was OK. I had 18v on my good ZSUS. That is about all the info I can give you on voltages.

Please check your buffer boards for bad FETs. You could blow new IPMs if you don't find them first. I had one blown on the lower Y buffer. If you don't know how to check them just dig around on google. That's what I did. Even without removing them from the board, one behaved different than the others when probed. Coppell sells them now also. When I had the bad one it killed my VSC voltage.

As far as IPM replacement, I strongly suggest from my research that you replace them both as a matched pair at the same time. Coppell is a good source for them. I will also add that neither of the two IPMs on my YSUS had any visual damage. The only thing that helped me key on the YSUS upper IPM as my source of trouble is that it had a snapping sound in rhythm with strobe-like flashes from the screen.

[bklein]

Re: 50" LG Y-sustain IPM modules

Arrgghhh.
Got terms Zsus and Ysus mixed up.
Zsus seems ok, cool IPM looked fine. 18V=18V.
Bad IPM on Ysus = YPPD-J015B. 18V=16.3V with both IPMs off the board.

[bklein]

Re: 50" LG Y-sustain IPM modules

I have read some conflicting information regarding the 18V supply on the Zsus board - whether or not on this board it should actually be 18V. I have both IPMs out of the board. The 18V on the board still reads 16.xV. Did they decide to run at a lower voltage or is the DCDC converter or caps bad on my board?

Also, if one IPM was blown on my Zsus, is it a good chance a Ydrive/buffer board is bad as well? One IPM on the Ysus ran cold other hot before I discovered the bad IPM on the Zsus board. I pulled the cold one and it was fine. Ysus 18V=18V.

[PlainBill]

Re: 50" LG Y-sustain IPM modules

By the way to remove the IPM modules from the board with minimal damage, I used an old Hand Copper made for soldering copper and lead sheet metal flashings for roofs, chimneys and plumbing pipes. I cut a slot along one corner of it with a hack saw. I let it sit and heat up with my propane torch blowing at it. I pointed the slot upward to create a trough and filled it with solder. I set the board over the hand copper with pins down and lowered it down so one row of pins dipped into the molten solder. A little wiggling and pulling and that side pulls out.

Interesting. I gather a 'hand copper' is the old fashioned soldering iron we heated with a blowtorch.

PlainBill