Resurrecting cracked Panasonic ST30...panel still shorted?

[jhdmia]

A ballistic Wii Remote cracked my Panasonic TC-P50ST30 and it shorted out and fried the SD (lower y-buffer) board. I replaced the board but left one of the ribbon cables from the panel disconnected where I found a short on the old SD board in case the panel was still shorted. The TV powered up and works fine but as expected there's a black horizontal strip corresponding to the disconnected ribbon cable.

My question is this: How can I determine if the panel is still shorted or if it was a momentary short from the initial impact? Where do I measure continuity?

[tom66]

Re: Resurrecting cracked Panasonic ST30...panel still shorted?

I can almost guarantee you that it will still be shorted. Testing is difficult, usually the lines short between each other or between themselves and the SS board.

[Alastair E]

Re: Resurrecting cracked Panasonic ST30...panel still shorted?

Well--IF the panel is cracked--Then it wont work at all, I'm assuming you've replaced the panel to have some picture, therefore the short whether intermittent or permanent in the old panel--Doesnt Matter--as its been replaced!

Just replace the buffer thats faulty.

[mmartell]

Re: Resurrecting cracked Panasonic ST30...panel still shorted?

Interesting. Would it not be possible to measure the ribbon itself to look for the short ? Maybe check against a know good portion of the panel to find what you're looking for.

[Alastair E]

Re: Resurrecting cracked Panasonic ST30...panel still shorted?

Prolly only show up with a high voltage applied....

Could rig up a current-limited 150V and try that....

Limit the current to a maximum of say 100uA and run an ammeter in series....

[tom66]

Re: Resurrecting cracked Panasonic ST30...panel still shorted?

A modern plasma panel will often work partially when cracked like an LCD, but there will almost always be a dead shorted portion which will kill buffer boards.

[jhdmia]

Re: Resurrecting cracked Panasonic ST30...panel still shorted?

Not surprisingly I couldn't identify any shorts with continuity any way I tried. On a whim I set the meter to volts AC, powered up the TV, connected one probe to ground and the other I ran along the ribbon with shorted wires and the one next to it to use as a control. I got ~24 volts on the non-shorted wires and ~4 to 21 volts on the shorted wires. I put a piece of tape over the area that was shorted (see image), plugged in all the ribbon cables, and confirmed that I got half of the dead strip back. Since the dead rows are at the very bottom the TV is 95% usable in this state. Thanks everyone who chimed in!

[tom66]

Re: Resurrecting cracked Panasonic ST30...panel still shorted?

I'm impressed you were able to make good from an otherwise bad panel. Let us know how it goes and how it lasts.

[mmartell]

Re: Resurrecting cracked Panasonic ST30...panel still shorted?

Hey not a bad save. Nice going.

[freakaftr8]

Re: Resurrecting cracked Panasonic ST30...panel still shorted?

Is there an actual crack in the panel?