50PB560B -LG common problems?

[Demonata08]

Hey everyone again, Been a few days. My newest project is an LG 50PB560B. Which actually has a very easily accessible service manual(which was nice).

So the initial problem is no power on. This model doesnt seem to even have a standby light. Tested all the power points and everything matched perfectly. Unplugged power board from main and the screen will come on. (i understand theres some way to get test patterns up but i havent figured that one out yet)

I'm highly suspecting the main. The board itself is a pretty simple looking board. but its going for 300 on ebay so not worth it. Im looking at reflowing it, i have everything i need to do that although im not experienced at all at that(Gotta start somewhere?)

Anyone know of the common chips to be looking at on this one? I have the diagrams to actually trace the problem but the test points are so tiny im sure ill short something. If anyone has any idea of the best plan of attack for this one id greatly appreciate the support

[Unspun01]

Re: 50PB560B -LG common problems?

You could try this repair kit for your 50" LG plasma model 50PB560B:

https://www.shopjimmy.com/lg-ebt6285...0pb560b-ua.htm

I have a similar problem with 60" LG plasma model 60PB5600... My 60" model has only one rear HDMI port, and they were notorious for poor solder. The HDMI port broke off completely when an HDMI cable was inserted. As a result, something was shorted out and damaged the main 156-pin IC LGE8220. I suspect you may have same problem.

Try holding your finger on top of the large LGE8220 IC and see if it gets hot.

You could try replacing the main IC, or buy the kit and replace all 3 ICs.

I doubt reflowing will solve your problem.

[Demonata08]

Re: 50PB560B -LG common problems?

Thanks for pointing me in that direction man! I agree that i believe it might be the main IC. But is there anyway to test? I feel like i should be able to since i have the actual diagram in front of me. But my hands are way to shaky to test points that small. Ill link the diagram below, and the manual also, if anyone smarter then i could follow through to a test point that might be a little easier, I would greatly appreciate it

Main IC
Service Manual

[Demonata08]

Re: 50PB560B -LG common problems?

Another question, Is there anyone that might know what voltage the RL_ON line would suppose to read? Im tracing the issue right now, the specs on the p board dont say. just says rl_on where it normally says voltage. The schematics i linked dont say either. under troubleshooting it just says to check the voltage

I'm getting .35 volts on that line. On some of the IC's that say it should be receiving 5volts its also getting .35 volts which leads me to believe that maybe needs to be 5volts. But im not sure.

thanks in advance

[Demonata08]

Re: 50PB560B -LG common problems?

You could try this repair kit for your 50" LG plasma model 50PB560B:

https://www.shopjimmy.com/lg-ebt6285...0pb560b-ua.htm

I have a similar problem with 60" LG plasma model 60PB5600... My 60" model has only one rear HDMI port, and they were notorious for poor solder. The HDMI port broke off completely when an HDMI cable was inserted. As a result, something was shorted out and damaged the main 156-pin IC LGE8220. I suspect you may have same problem.

Try holding your finger on top of the large LGE8220 IC and see if it gets hot.

You could try replacing the main IC, or buy the kit and replace all 3 ICs.

I doubt reflowing will solve your problem.

Tried the repair kit. No dice.

replaced all three IC's in the repair kit. cant even get an error code of any sort unless there is no power to the main.

when its all plugged up it does nothing when you hit the power button. That repair kit had a new eeprom, a chip for what i think is audio, And the new main IC.

the ic doesnt get hot or anything. i checked to be sure the button was having a voltage fluctuation when pressed and it was working.

These mains are way to expensive to really be worth it. anymore tips? I went through the the voltage regulators both were working i believe. it 5.2 to 3.3 and 5.2 to 1.8.

[Demonata08]

Re: 50PB560B -LG common problems?

I really hate to keep posting but im not getting any replies. And im still trying to actively repair the board since the replacements are stupidly high. So i double checked the panel and all other boards are good. I got the test patterns on and it was working well.

In the attachment is troubleshooting steps from the LG, Since the IC replacements ive gotten all the proper voltages on everything on the list except maybe to the main IC. it was showing 3.3v but i got 3.2v which i think is close enough? I checked the regulator and its putting out a perfect 3.3v.

Ive made it down to checking the clock speed at X400 for 24mhz. I have no idea how to go about that. the other two are to check signal transitions at different places which i dont know how to do that either.

So what component should i be looking at? Theres a few on here that i suspect and would like to test. I'll mark them on a reupload of the main. its the ones between the red lines.

I feel like theres so many of these TV's with main board issues. Every time i search its model the majority of them have the same issue but no solution. With the schematic i feel like we can figure this out.

[Demonata08]

Re: 50PB560B -LG common problems?

Dont suppose anyone has any wisdom for me at this point? I realized my pictures didnt upload so here they are

[diif]

Re: 50PB560B -LG common problems?

It looks like you need an oscilloscope for those last three tests.

[Demonata08]

Re: 50PB560B -LG common problems?

It looks like you need an oscilloscope for those last three tests.

Ahh gotcha. Im not super familiar with those but its good to know what i need.

What im curious is, Would it be an issue for the main chip to be expecting 3.3v and gettin 3.194v that was one possible issue with the voltage. the other was 1.15 getting 1.17v which i figured was pretty close on that one.

[budm]

Re: 50PB560B -LG common problems?

Ahh gotcha. Im not super familiar with those but its good to know what i need.

What im curious is, Would it be an issue for the main chip to be expecting 3.3v and gettin 3.194v that was one possible issue with the voltage. the other was 1.15 getting 1.17v which i figured was pretty close on that one.

Look up the spec sheet to if it is out off spec or not.

[Bloopeta]

Re: 50PB560B -LG common problems?

Did you ever get anywhere with this?? I have the same problem

[Unspun01]

Re: 50PB560B -LG common problems?

Tried the repair kit. No dice.

replaced all three IC's in the repair kit. cant even get an error code of any sort unless there is no power to the main.

when its all plugged up it does nothing when you hit the power button. That repair kit had a new eeprom, a chip for what i think is audio, And the new main IC.

the ic doesnt get hot or anything.

The repair kit should have solved your problem. The mainboard is your problem - especially since every other board appears normal and you see a test pattern screen with mainboard disconnected.

The repair kit has 3 ICs: Main IC (IC400), Audio IC (IC606) and SPIFLASH/EEPROM (IC505).

In all likelihood, only Main IC400 is bad, but you cannot get the part separately anywhere else so you have to buy the 3 part kit. The other 2 ICs (audio IC and EEPROM) could have been kept aside for now.

Audio IC (IC606):
If bad, Audio IC could pull down voltages and prevent main IC from getting correct voltages, and perhaps no standby LED. If bad, IC would likely get hot but I think you checked this. If bad, TV may not start, but even if audio IC is completely removed TV should start (no sound) if all else is good. Audio IC is not usually the problem and didn't need to be replaced.

SPIFLASH/EEPROM (IC505):
If bad, would usually prevent the TV from booting correctly, but you should still see standby LED on front of TV. SPIFLASH/EEPROM likely not your issue and didn't need to be replaced.

Main IC (IC400):
Totally dead TV as you describe still points to the main IC LGE8220. There could be a few things at work here:

1) Is the IC installed in correct orientation? It is possible to install 180 degrees out of place.

2) This IC is not easy to work with due to fine pitch between pins. Check under strong magnifying lens (or with multimeter) to ensure no shorts between adjacent pins which should not be connected.

3) You may not have solder bridging adjacent pins, but with 156 pins, it's possible some aren't soldered at all.

I do not know if you used hot air rework station, or infrared solder station, or manually soldered each and every pin. You didn't say.

With hot air or infrared - if you did not adequately heat the area, you may have some pins making good connection, and some pins making no connection. You may need to re-touch some with fine-tip solder iron.

I strongly advise you to RE-EXAMINE all of your solder connections under good light with strong magnifying lens to ensure you do not have any solder bridged between adjacent pins, that the IC sits completely flat against the board and that every single pin is actually soldered.

Can you please upload high resolution close-up photos of your solder work on the main IC and audio IC under good light from a few different angles?

[Helikvar]

Re: 50PB560B -LG common problems?

Hello everyone. My second post though I have been following this group for a year or more.I too have a 50PB560B that was completely dead when brought to me.The HDMI port had been completely torn out from the main board along with several resistors and a few transistors.Some tracks in the board were damaged as well.Searching the internet found nothing for a main board .Out of stock was all I found.But thanks to the schematics in this thread I was able to replace all of the missing components. Still need to fix a few traces but by jumping a mosfet on the main board I have gone from a completely dead set to turning it on and off and displaying the menu and all its functions.I even have the led lit up now while off. I had to order the p-ch mosfet that I jumpered and should have it in a week or so.I should know then if that is the issue with it.I was going to buy the repair kit from jimmys but did some more trouble shooting with the schematics in hand and found that the mosfet was not turning on or off . The mosfet supplies 5v from the 5v-stb which goes on to provide 3.3v 1.8v 1.15 volt.This is the mosfet I jumpered which seems to have restored most of the functionality.The mosfet is Q604 and is switched by Q603 an NPN transistor.Jumpering the Drain AND Source of Q604 is what gave the set functionality again.I will update this post once the new mosfets arrive and are installed.

[jp_fizzer]

Re: 50PB560B -LG common problems?

Hello, I have a 50PB560B and I started having an issue where I would have to try turning the TV on and off several times before it would finally turn on. The standby light would always go on and off, but the screen would just stay black. Now, I cannot get the screen to ever come on, although the standby light still switches when I turn the power on and off. I have thoroughly checked all the boards and cannot find any suspect looking components, no bulging, no leaking, no charring.

I have checked the voltages on the P600 connector on the main board as well as P811 on the power board. I think they look okay compared to the diagrams printed on the boards, here are the voltages:

P600:
pin 1: 17.3V
pin 3: 0
pin 5: 5.2V
pin 7: 5.2V
pin 9: 0
pin 11: 0
pin 13: 5.2V
pin 15: 1.5V
pin 17: 3.2V

P811:
pin 1: 201V
pin 2: 201V
pin 3: blank
pin 4: 0
pin 5: 0
pin 6: 0
pin 7: 5.2V

I really have very little experience but would love any help anybody is willing to give. Does anybody have any suggestions for what I can check next?

thank you very much.

[jp_fizzer]

Re: 50PB560B -LG common problems?

So I have tried disconnecting all of the various boards one at a time and powering it up but never any difference so I have no idea which board might be the problem. I have read about some people having success reflowing the boards in their oven. As a last ditch attempt to revive the TV is there any point in putting the power board and main board in the oven?

[Unspun01]

Re: 50PB560B -LG common problems?

DO NOT place the power board in the oven. Ever. You will create irreversible damage. This is not a fix for power board on this TV or ANY TV.

NO NO NO.

Also, DO NOT put this mainboard in the oven. This model of tv does not have BGA main IC processor chip so this is not going to fix either and may cause irreversible damage to your board.

Let me be clear, some people have had luck with TEMPORARILY repairing certain models of LG plasma, LED and LCD tvs that have BGA main processor IC under a heat sink that was known to warp the circuit boards over time.

This is not the same type of mainboard . OVEN IS NOT A FIX.

[dick_barton]

Re: 50PB560B -LG common problems?

You don't say what the various pinouts for P600 ans P811 are?? They should all have names alongside them as shown on the circuit board.

There should be a white label on the back of the plasma screen giving the various voltages that should be present. It looks like you're missing VA to start with but that could be for other reasons.
Can you post a picture of the label as well as the boards and one showing alll the boards connected to each other.

[jp_fizzer]

Re: 50PB560B -LG common problems?

Ok, so I did some more research on the subject and decided not to bother baking the boards yet. I put everything back together and the TV turned on. I cycled the power and it would not come back. So I unplugged all the boards again and plugged them back in. There was a huge spark when I plugged in the P811 connector but when I turned the TV back on this time it came back on. I have checked all the voltages with the TV on and they are all the same except that pin#6 on P811 is now at 55V where as it was 0V when the TV was plugged in but not working. Is this the key? Does anybody know what that might mean?

Also, there is a small board below the power board that has 4 ribbon cables coming into it. It has IC704 on it which is very hot to touch. Also, D401 on that same board is now flashing, it was not on when the TV was not working.

Any suggestions would be greatly appreciated.

[dick_barton]

Re: 50PB560B -LG common problems?

Can you post pictures of what you are refering to. The 55V is your VA supply. I would be looking at the solder joints on the Zsus board and ensure that they are all good.
What is the part number written on IC704???

Remember that we don't have the set in front of us and probably have never worked on this model before.

Edit
IC704 is the XD engine on the Logic Board and will run hot.

[Unspun01]

Re: 50PB560B -LG common problems?

This is a plasma TV model. It has a logic board located directly in center of TV below the power board. It has a built-in self test feature that can test the panel and panel driving boards without a mainboard connected.


1) UNPLUG THE TV.

2) Disconnect the cable between the mainboard (the one with AV inputs) and the logic board. It shouldn't matter which end of the cable you unplug.

3) On the logic board there are 2 open-holes that can have a small jumper inserted ( like a small paperclip). The two points have a label printed on the board called AUTO_EXT_GEN or similar. Spend a few minutes looking for it - you'll find it.

4) Insert a bent paperclip into both holes of the AUTO_EXT_GEN holes with mainboard disconnected and plug in the tv.

5) If power board and other panel boards are ok you should see test patterns display on your panel automatically.

Make sure that you do not insert the paperclip or jumper wire too far. You do NOT want the ends of the paperclip or wire to contact the logic board and the metal underneath that is the back of the panel (it is grounded).