Lg 60pz550

[krygods]

When I got this TV it would turn on and shut itself right off.

Diagnosed it down to being a bad ZSUS by following Toms guide.

I repaired the ZSUS with the repair kit from ShopJimmy.

TV powered up and worked great for about 30-45 minutes, when I looked at the TV again I had a picture looking like this.

Anyone know what the cause of this would be?

[freakaftr8]

Re: Lg 60pz550

That looks like your Z sustain board failed. Are you sure you did a good soldering job on all replaced components? Check the fuses on the Z board see if any of them opened

[krygods]

Re: Lg 60pz550

yea i'm positive i did a proper job on the soldering

im opening the tv back up right now, let you know what i find

[krygods]

Re: Lg 60pz550

Fuse on the Z sustain board is fine

Any suggestions to narrow down the cause?

[tom66]

Re: Lg 60pz550

Check Vzb voltage. Definitely a Z-sustain issue.

[krygods]

Re: Lg 60pz550

VZB is showing 41.92VDC

[freakaftr8]

Re: Lg 60pz550

Check soldering on all coils on that board. Even if they look good try to resolder them make sure that they're making a good connection. There's a possibility you might be seeing the reason the board blew in the first place happening all over again

[tom66]

Re: Lg 60pz550

VZB is showing 41.92VDC

Much too low -- needs to be around 90-120V for an LG 2011 panel.

[krygods]

Re: Lg 60pz550

So even after I check all these I'm assuming that I'm going to need a new repair kit for the Z sustain board?

If this is the case is there any testing that can be done after the new repair kit is installed to avoid this same problem of the Z sustain blowing again?

[krygods]

Re: Lg 60pz550

Inductor coil solder joints look good no cracking nice and shiny.

All but one coil did have 'ring around the collar' cracks but I touched them all up while installing the repair kit from SJ

[tom66]

Re: Lg 60pz550

Have you tried adjusting the Vzb point?

[krygods]

Re: Lg 60pz550

No I will do that right now.

[krygods]

Re: Lg 60pz550

VZB adjustment causes no change in the voltage.

Also noticed if the probes are left on the VZB test points the voltage starts to steadily drop.

Also noticed that VZB DCV is never the same, sometimes starts around 80 DCV sometimes 60DCV and I've even seen it as low as 46DCV before the voltage starts slowing dropping off.

[krygods]

Re: Lg 60pz550

I found a Z Sus board on ebay that will arrive today.

Question: Is there any risk in just putting the Z Sus into the TV and testing to see if it works, or is it possible for something else with a problem in the TV to burn up the Z Sus?