LG 60PV450 plasma burning/melting plastic on z-sustain

[progrmmer]

I originally had the issue outlined in this thread - Lg 60pv450 colors flashing . I was able to fix it by re-soldering a couple joints on the ERC inductors as suggested by Tom. That worked fine for a few weeks, but this past week I started to notice the smell of burning plastic so I took the back off and discovered a part of the z-sustain sub board was indeed melting. Pic attached.
I've decided to just buy a new z-sustain board (my soldering was poor at best) but am having trouble detaching the copper ribbon in the pic from the melted part. It looks like the melted clip is not all the way un-fastened and I cannot push it in or out due to the melting. Any ideas on how to free it w/o damaging the ribbon?

[Shinju]

Re: LG 60PV450 plasma burning/melting plastic on z-sustain

I would replace that Zsus buffer board too if you didn't already order one. As far as getting the ribbon out, take the zsus out, detach the buffer board and try pulling out the ribbon by moving the free floating board back and forth gently.

Did you take any VZB voltages while it was in this state?

[tom66]

Re: LG 60PV450 plasma burning/melting plastic on z-sustain

Looks like the Zsus common ribbon was not properly seated and this has caused a lot of heating on the contact surface. How many ribbons does this set use on the Z side?

[mmartell]

Re: LG 60PV450 plasma burning/melting plastic on z-sustain

Maybe get a screwdriver GENTLY in there and use a twisting motion (with board still mounted) to unlock the connector. Hope it's not melted in there or could make the panel toast.

[Shinju]

Re: LG 60PV450 plasma burning/melting plastic on z-sustain

Looks like the Zsus common ribbon was not properly seated and this has caused a lot of heating on the contact surface. How many ribbons does this set use on the Z side?

3 zsus panel ribbons.

[freakaftr8]

Re: LG 60PV450 plasma burning/melting plastic on z-sustain

If you can get the ribbon loose I would look a the ribbon and if it has burn marks on the copper take a very mild scotchbrite and clean the copper contact

[tom66]

Re: LG 60PV450 plasma burning/melting plastic on z-sustain

From my testing on multiple panels the ribbons are all common to each other both on the Z-sub board and on the panel (that is, if you continuity-meter them, they'll show short.) In theory these panels should work ok with a single ribbon only. But looking at the glass on other panels before, there's very little electrode width connecting them... i.e. a lot of resistance... this could mean that if the other ribbons were loose or poorly seated, one ribbon took the majority of the drive current...

[Shinju]

Re: LG 60PV450 plasma burning/melting plastic on z-sustain

Going to ask an obvious question. You had ALL the Sustain screws in and tight right? You cannot have even one missing or it will cause issues.

to me it looks like his ribbon lock wasn't locked but in the unlocked state.