LG 60pz550 sound but no picture

[rendog33]

Re: LG 60pz550 sound but no picture

2 more with laptop feed.....please see pics on previous page.

[rendog33]

Re: LG 60pz550 sound but no picture

I'm about to replace the z-sus but would like to know if the pictures above and at the end of page 1 seem to point to a bad z-sus board. Thank you.

[freakaftr8]

Re: LG 60pz550 sound but no picture

That's what I would do. Looks like a classic case of zsus failure

[rendog33]

Re: LG 60pz550 sound but no picture (fixed)

Thank you all for your help. I was going to purchase a new Z Sus board from electronic bay and the same seller said that it might be cheaper to just send in my board and they would repair it.

Well, I sent it in and they sent it back fixed. I re-installed it and now my TV works.

I was not in a position financially to purchase a new TV and because of the help on this site, I was able to have my TV fixed for $100. I'm very grateful, Thank you!

[Nick's Tvs]

Re: LG 60pz550 sound but no picture

Cheaper repair available here
http://www.nickstvs.com/store/p612/L...Repair-Service

[skyblaster]

Re: LG 60pz550 sound but no picture

Reviving an old thread since I just picked up the same model with similar symptoms. Sound but no picture. The seller informs me that the panel was working fine up until it went black screen, while retaining sound.

First thing I did when I got home was pull the Zsus. I've verified there are no shorts on any of the FGFP4633 IGBTs (all measuring 10kOhms), or blown fuses, or burnt resistors, just two cracked solder joints on two separate inductor coils.

My plan of attack is to simply reflow the coils, reinstall, and verify all voltages.

Are the coils on the Ysus worth inspecting, or is it usually just the Zsus on this model?

[tvtimmy]

Re: LG 60pz550 sound but no picture

Check everything now while you have it apart.

[Andrew F. Ali]

Re: LG 60pz550 sound but no picture

Take some voltage 'vital signs' measurements:
1. Va =
2. Va =
3. Vsc =
4. Ve =
5. Vzb =

[skyblaster]

Re: LG 60pz550 sound but no picture

Repaired the cracked solder joints on the Zsus board and reinstalled.

	Measured	Panel Rating
Va	55.13		55
Vs	201.6		201
Vsc	149.0		150
Vy	-177.6		-178
Vzb	105.7		110
M5V	5.166

I disconnected the LVDS cable and jumpered R51/R52 and confirmed I can display test patterns. It's not a perfect panel as there is a single black line showing on solid red and blue screens, but I digress.

With the jumper pulled, there is nothing on screen and I'm not hearing any audio when attempting to blindly cycle through the inputs with HDMI connected to my laptop. The laptop does recognize the TV and sets it's output to 1080p accordingly.
I also connected the Ethernet port to my router, however the link LEDs do not illuminate.
I'm guessing the issue is with the main board, part EBT61533410 (EAX63546403). Any chance it's not a BGA soldering issue? I just read the following post and don't like the prognosis: https://www.badcaps.net/forum/showthread.php?t=71302

[Andrew F. Ali]

Re: LG 60pz550 sound but no picture

Good job!!

[landen_michael77]

Re: LG 60pz550 sound but no picture

Hi guys. I had one of these dropped off today. I think one of the copper coils is cracked on the zsus. Is there a way to test and be sure that is what is causing it to have no picture?

[tvtimmy]

Re: LG 60pz550 sound but no picture

Remove the useless lead-free solder and re-solder them all wirh leaded solder. Don't try and use the 1/8 thick plumbers solder, it won't work. Then test the set.

[landen_michael77]

Re: LG 60pz550 sound but no picture

I resoldered them on both z, and y before posting the question.

[tvtimmy]

Re: LG 60pz550 sound but no picture

Put your meter in continuity mode(beeps when probes touch each other) and check for shorts on the igbt's mounted to the heatsinks. Any beep means there is a short. These have 3 legs, and don't worry about the diodes.

[landen_michael77]

Re: LG 60pz550 sound but no picture

Can i just put ground probe, on back of the panel, and just touch each pin with hot probe?

[tvtimmy]

Re: LG 60pz550 sound but no picture

I wouldn't. Pull the board and check them from the bottom side.

[landen_michael77]

Re: LG 60pz550 sound but no picture

TV Timmy. Here are some pics. The red circles i get beeps with my multimeter in continuity mode. Pictures are of the top, and bottom area of board where i tested. They are out of order for some reason.

[Unspun01]

Re: LG 60pz550 sound but no picture

landen:

Thanks for those photos.

If you look closely, you will notice that all the points you measured with beeps (pins 1-3) are physically connected by trace on the PCB. This does not correctly test these components.

You need to measure all of the 3-Pin diodes and IGBTs/Mosfets pins 1-2, 2-3, 1-3 for shorts.

Diodes rarely fail on these TVs. Please measure all 3-Pin IGBTs that are heatsink connected whose component markings begin with E or Q.

Please visit the thread below and follow my troubleshooting advice with the attached markup pictures:

www.badcaps.net/forum/showthread.php?t=74898

[tvtimmy]

Re: LG 60pz550 sound but no picture

+1
The parts you have in the second picture are diodes, marked with a D. They are connected together.