Z50PJ240 Powers on then back off clicks but no picture

[Brentsky]

I have a Zenith/LG Z50PJ240 Plasma TV that tries to turn on but then shuts back off. After reading that the EAY60968801 Power Supply had a known common issue that could cause this clicking sound but not powering on I rebuilt the power supply using a rebuild kit from ebay. It didn't solve the problem so I figured maybe it just took the power supply out entirely and bought a new power supply board and it to made no difference. I have tried disconnecting every single board 1 by 1 and 1 at a time and it didn't matter it still had the same exact issue. When it tries to turn on there is no flicker or anything you just here a click and the led blinks once and you can see the optical audio port light then it clicks and go's back off and tries once more before it just sits there as if it were off... Can anyone point me in the4 right direction here as to what to do to troubleshoot this TV and isolate the problem so I know which board to replace or look at for the problem? Thanks...

[tom66]

Re: Z50PJ240 Powers on then back off clicks but no picture

Can you post some pictures of the boards in the chassis?

[Brentsky]

Re: Z50PJ240 Powers on then back off clicks but no picture

Ok so I found that if I disconnect the large white connector going from the power supply to the ysus board it seems to not cycle when it's powered on. it seems to stay on just nothing on screen. if I disconnect all the wires coming out of the ysus board as well as the flat ribbons for the screen itself it still shorts out so only disconnecting the ysus board seems to stop that cycling. here are some photos and let me know if there is anything you need a closer image of. Thanks greatly...

[Brentsky]

Re: Z50PJ240 Powers on then back off clicks but no picture

Here is a link to more photos of the boards.

http://s222.photobucket.com/user/brb...?sort=3&page=1

[Brentsky]

Re: Z50PJ240 Powers on then back off clicks but no picture

Ok so upon further inspection I noticed I seem to be missing a capacitor on this board c105 ga102 ga517 it's in the location right next to where the long flat white ribbon connector is corner from the long aluminum/chrome heatsink is. you can see in this photo the capacitor is shown. Does anyone know what size that capacitor is ?

[soog35]

Re: Z50PJ240 Powers on then back off clicks but no picture

Wow, I can't believe you just posted this today. I have the same exact model tv you have. Just got that kit off ebay today. Replaced all the parts tonight and mine too still clicks. Now looking for more answer and came across your post. Please let me know if you figure it out and it never gets posted. I would really appreciate it. My email is soog35@roadrunner.com Also mine has 2 capacitors.

[soog35]

Re: Z50PJ240 Powers on then back off clicks but no picture

Tomorrow night I will try disconnecting the connection like you did and see if I get the same results you did.

[Brentsky]

Re: Z50PJ240 Powers on then back off clicks but no picture

I will absolutely keep you posted Soog. I ordered a new Ysus board tonight though the place I ordered it from now shows none in stock and a very different price so I am a little worried they may not have the part I ordered. I will get it figured out one way or another and will post back with an answer. Have you tried unhooking boards 1 by 1 yet to see if there is a shorted board elsewhere. when I removed the large white thick cable connector going to the Ysus board (Big board on left if looking from the back) to the power supply board (big board in the center ) the TV would suddenly not click back off or cycle like it does if it's connected. obviously only disconnect them when the power plug is off and all residule power is cleared. Does your Ysus board have the 2 capacitors I mention in the post above ? if so could you get me the numbers from the one circled in this photo

[tom66]

Re: Z50PJ240 Powers on then back off clicks but no picture

Manufacturers sometimes change production runs, like for example removing a cap, without changing a part #.

[soog35]

Re: Z50PJ240 Powers on then back off clicks but no picture

Here is the capacitor your looking for.

[soog35]

Re: Z50PJ240 Powers on then back off clicks but no picture

This one is a little clearer. Still sideways though, sorry.

[soog35]

Re: Z50PJ240 Powers on then back off clicks but no picture

I tried disconnecting each board separately, then both boards at once and the tv still just clicks right back off when you turn it on, no matter what i did. I do notice after the tv is unplugged for a long time, the green light on the green control board will light up one time then go off, when the tv goes off. After that every time I try to turn it back on, no green light and of course the tv clicks right back off. I did see a test on the control board somewhere, but it was a different plasma tv. Hope someone can point us in the right direction, until then I guess I'll just keep searching through the forum and maybe find something.

[tom66]

Re: Z50PJ240 Powers on then back off clicks but no picture

Can you post a close up picture of the control board?

[soog35]

Re: Z50PJ240 Powers on then back off clicks but no picture

Here it is. Is there a chance that this could be the problem?

[tom66]

Re: Z50PJ240 Powers on then back off clicks but no picture

Not necessarily; but there's a test that can be done on it to see what might be the cause of the problem.

Just to the bottom right of the LG branded "XD" processor (the plasma display panel DSP) there are two holes marked EXT AUTO GEN. You need to take a small bit of wire and jumper these holes together.

Then, using your image orientation as a reference, the top most cable is to be disconnected.

Plug the TV in. Test patterns should appear on the screen if all is well with everything -except- the main board which is a common fault on these models. If the TV continues to click on and off, there is one other thing that needs to be jumpered, but hopefully we can avoid that on this model for now.

[soog35]

Re: Z50PJ240 Powers on then back off clicks but no picture

Are you talking about disconnecting the cable that goes to the (main / av / tuner board)?
And that is the board that goes bad a lot in these models

[tom66]

Re: Z50PJ240 Powers on then back off clicks but no picture

Yes, I am talking about disconnecting that cable, the main board is a common fault on this model, Y-sus and Z-sus are reasonably reliable.

[soog35]

Re: Z50PJ240 Powers on then back off clicks but no picture

Ok, I will try it when I get home after work and let you know. Also I did replace a diode and voltage reg that came in the repair kit on the power board. When i tested the diode it gets no reading.The tv did power on for a couple of minutes then went off. Then it was back to just clicking off every time I tried to turn it back on . The tv was unplug all week though. So I figured it was liked I stated above about the green light coming on when it sits for a while. Thought I should mention that in case that makes any difference.

[soog35]

Re: Z50PJ240 Powers on then back off clicks but no picture

I did the test with the jumper wire and it still clicked off when I turned it on. No test pattern screen, nothing, just clicked off. I'm guessing that if I had test patterns appear, it would mean the problem would be in the main board. So does that mean the main board is probably not the problem?

[tom66]

Re: Z50PJ240 Powers on then back off clicks but no picture

Maybe, but it also indicates there is one additional jumper test we need to do. You will need a pair of 100 ohm resistors, can you get some? They will need to be jumpered on the power board to main board connector. Unplug the connector from the main board end, and connect the pins STBY 5V and PS ON and STBY 5V and VS ON. If you need help locating the pins, post a picture of the legend printed next to this connector.