Vertical 1" wide black bars on a plasma

[dmbj]

I picked up this daewoo 42" plasma last night (for $25) with about a 1" wide vertical black line about 4 or 5 inches from the left side of the screen looking at it from the front of the set.

inside along the bottom of the screen there are 7 sets of ribbon cables that go to the display

each of those seem to have 4 section that they control, So my problem was with cable #2, section 1 of 4.

so I reseated the 2nd ribbon that controlled this bad section and that did fix the problem however...

shortly after the black bar came back in ribbon #3 section 1, so i reseated that one and it was fine. then it jumped to ribbon 5 section 1. I reseated all 7 at this point.

The set ran for about half an hour then went back to the original problem ribbon #2 section #1

so the problem seem to always be in section 1 of the 4 in each ribbon cables

I'll have pictures and even the model number later but thought i would throw this out there just for anyone reading this to ponder what could be the problem.

The only picture I have right now will not help, this is when it was working for a little while last night

[netdent]

Re: Vertical 1" wide black bars on a plasma

If it has an LG screen (I suspect it does) on the underside of the ribbon cable below the metal plate there are some surface mount components on the ribbon cable, you will probably find the resistor has gone dry jointed, soldering is tricky, if you over do it it will ruin the panel

Ronnie

[dmbj]

Re: Vertical 1" wide black bars on a plasma

If it has an LG screen (I suspect it does) on the underside of the ribbon cable below the metal plate there are some surface mount components on the ribbon cable, you will probably find the resistor has gone dry jointed, soldering is tricky, if you over do it it will ruin the panel

Ronnie

Yes there are 4 on each, they all say 100 and read 10.5 to 10.6 ohms on the top of the resisters, I could not get a good reading from the cable, and could not figure out a good place to even test them in circuit

[netdent]

Re: Vertical 1" wide black bars on a plasma

Yes there are 4 on each, they all say 100 and read 10.5 to 10.6 ohms on the top of the resisters, I could not get a good reading from the cable, and could not figure out a good place to even test them in circuit

I think it's best to just reflow some solder on the section or ribbon where you have the problem, not too much heat in case it melts the plastic ribbon, I have repaired a few of these now, try using a magnifier you may see the cracked solder joint, good luck

Ronnie