LG 60PZ550 Sound/No picture

[mikeburns]

I have tried powering up with the Y or the Z SUS disconnected.
I have measured VS going into both Y and Z and it is the 203V on the sticker.

I have tried a new power supply board.

I tried disconnecting the main board ribbon cable from the control board and jumpered R51 and R52.

The panel appears unbroken. The unit was turned on when it went black.

The TV stays on and the remote control works.

I noticed a capacitor has fallen off the control board at location C12. Not sure if this happened after I took the back off and maybe my dog brushed by? But when I hold it in place, still no image. (Not sure when I hold it that it is making good contact, though.)

Is there another test I can try or another voltage to measure? As I remember, Va was good too, and there was negative voltage on the Y SUS out and positive on the ZSUS.

The only problem the TV had was a intermittent failure to sync up with HDMI inputs,which happened with multiple devices on multiple HDMI ports on the TV.

Thanks for any guidance you can supply, even if it is to give up!

[MagicSmoke]

Re: LG 60PZ550 Sound/No picture

If part fell off control board then that is likely the problem. Control board sends the signals for the display. Need pics of area where cap fell off.

[tw2005]

Re: LG 60PZ550 Sound/No picture

is the activity LED lit on the logic board?

[mikeburns]

Re: LG 60PZ550 Sound/No picture

is the activity LED lit on the logic board?

Thank you. There is a green LED that flashes when the TV is on.
This is on what I call the control board, the one that the cap fell off of.

I will send a picture of the board with the missing cap. It goes where it says C61.

[tw2005]

Re: LG 60PZ550 Sound/No picture

Thank you. There is a green LED that flashes when the TV is on.
This is on what I call the control board, the one that the cap fell off of.

I will send a picture of the board with the missing cap. It goes where it says C61.

ok, well sounds like the control board is active.

[mikeburns]

Re: LG 60PZ550 Sound/No picture

ok, well sounds like the control board is active.

Yes, it is definitely getting power. I have had the back of the TV off for several days and only noticed the capacitor today. It was hanging askew and when I touched it it fell off completely. So it may have been disconnected the whole time.

I don't know if a bad control board could cause these symptoms, but if it can, I will probably invest in one.

Thanks for your help.

[mikeburns]

Re: LG 60PZ550 Sound/No picture

If part fell off control board then that is likely the problem. Control board sends the signals for the display. Need pics of area where cap fell off.

Thanks MagicSmoke. If the control board is bad, is there a test for that?

[MagicSmoke]

Re: LG 60PZ550 Sound/No picture

Looks like that cap is protecting IC52, cant read what chip it is from pic.

There should be a place to jumper on control board for test patterns. Cant see where it is from the close up pic.

[mikeburns]

Re: LG 60PZ550 Sound/No picture

There is a place on the control board for a test pattern R51 and R52.
I put a little paper clip into both holes and disconnected the ribbon cable to the main board but there was nothing on the screen.

I have the TV set to an RF channel that give static. The static was still there when the jumper was in, I think.

Here is a picture. I had reconnected the ribbon cable before I took the pic.

[Shinju]

Re: LG 60PZ550 Sound/No picture

What are your VSC,-VY and VZB voltages?

[mikeburns]

Re: LG 60PZ550 Sound/No picture

What are your VSC,-VY and VZB voltages?

VSC -109
VY 69
VZB 11

Maybe I should say that I have an analog meter. When I Read VSC I have to switch it to negative DC.

Maybe I can't use this meter?

[Shinju]

Re: LG 60PZ550 Sound/No picture

Voltages are low, do you have a digital meter?

[kudalski]

Re: LG 60PZ550 Sound/No picture

I'm having the same problem with this same model TV. TV behaves as its working but no image at all.
All voltages are correct.
Main and controller boards worming up as to normal.
Y and X sustains stay cold. but correct voltages going in and out.
any idea..? thank you

PS. Just looked through the threads and noticed yes my tv has a glowing screen but no picture. so I am following that thread now. that's where I needed to be.