LG 50PG60 plasma TV not turning on, blinks four times - what is the problem and how to repair

It's been a while since I posted in the blog and it's because we are so busy with work lately.

Unlike other articles, this one will not be based on personal experience with this particular model.

It's just a question we received and my answer to it for all I know.

The logic here is fairly applicable to many other similar situations.

Question:  
LG 50PG60 TV won't cut on. The power light blinks four times and that is all it does.

Coppell TV Repair's answer:
First things first: I have to say that I have not worked on that particular TV model. 
When I do I'll revise this page to be more specific.

It would be a good thing to know if the power supply clicks when the TV gets powered on or not.

That would say if the power board is functional enough to at least recognize the power on command and process it to the point where it tells the power supply to wake up.

Here are the most likely possibilities based on experience:
1) A bad power supply board EAY43510801 failing to start up as expected

2) A bad main board fails to either wake up the power supply or continue the TV initialization process once power is generated.

3) Another failed board preventing the TV from coming up as being detected by either power or main board and causing it to signal error and shut off.

Let's quickly review the three possibilities and how do you test and eliminate each with what's handy:

1) A bad power supply board EAY43510801 failing to start up as expected  
With the note that I have not worked with this particular board, I've worked with several others that are used in brother and sister models of the LG 50PG60 and I would hazard a guess that the PSU (power supply unit) EAY43510801 can be tested fairly quickly and easily.

I won't type the details again here, but you can read one of the following articles, which explain it:

http://blog.coppelltvrepair.com/2013/09/how-to-test-lg-eay60968801-power-supply.html

http://blog.coppelltvrepair.com/2013/06/question-about-repairing-power-supply.html

http://blog.coppelltvrepair.com/2013/04/lg-50pg20-not-turning-on-is-power-board.html 

They all say basically the same thing, so it shouldn't be hard to apply to EAY43510801at all.

If the test doesn't pass you can contact us for a repair service on your EAY43510801.

Until we gain some hands-on experience with the board there won't be a listing for it, but I can tell you that we can't charge more than $70-$80 for repair for purely practical reasons. If we can't fix the board or it is too costly to fix the only thing you'd end up paying is the return shipping for the board - no parts and no labor.

2) A bad main board fails to either wake up the power supply or continue the TV initialization process once power is generated.
That can be somewhat hard to test and frankly the best thing to do is to leave that option for the last and rule out the others.

Short of hearing or seeing someone who's seen this problem multiple times and telling you what exactly to look for the best way to test a main board for an issue is to have it replaced with another.



3) Another failed board preventing the TV from coming up as being detected by either power or main board and causing it to signal error and shut off.

While this could be any board that is monitored (and the power supply board monitors most if not all of its output voltage lines) the two most likely candidates for that are the two boards that consume most power and those are the two sustain boards - the YSUS (Y-main) and ZSUS (also called X-Main).

The below instructions are only focusing on testing the YSUS and ZSUS boards. That leaves open the possibility of another board causing the failure, so do not forget about it if all tests here pass!

YSUS in 50PG60 is EBR41728701  and ZSUS is EBR50044801, but you won't need those numbers before you suspect any of them as a problem.

A sustain board can be bad in different ways and can cause different misbehavior, but specifically when TV does not come up (meaning front LED not staying in solid "on" state - blue or green or whatever indicates "on") then there is a relatively simple way to see if a sustain is in the way: disconnecting it from the power!

I instantly want to note that this is not true for all TV makes and models. Panasonic plasma TVs usually would not tolerate, but most LG based plasmas and many Samsung ones, especially older ones (I just haven't seen enough of the generations after 2009 to know) would also allow it.

So in a nutshell you just disconnect the YSUS board from the power supply and try to turn the TV on.
If the YSUS (or the buffers after it) were either shorted or just badly overloading the power supply and causing it to shut-off itself, then by removing them you remove the problem and the TV would happily come up, even without a screen.

If so then you know you have a bad YSUS and/or buffer boards.

If so you can search for EBR41728701 and possibly the buffer boards.

If no help, then you usually want to connect the YSUS back to the power and disconnect the ZSUS EBR50044801 for another try.

Disconnecting the power supply only is usually sufficient. Sometimes - rarely yet sometimes - you'd have to disconnect the data signal cable too as a damage can be showing through it and causing the shutdown.

Basically this is how far I can take you this time...testing the power and the two sustains (with some limiting conditions) as the most common sources of problems in plasma TVs.

If those quick tests don't help I'd go for a commercial advice.

Good luck!