Panasonic th-42pz70ba SU board or panel

[efwiofoi]

I have a panasonic th-42pz70ba, i've narrowed the fault down to the SU board(or board+panel). the tv powers up without the SU board connected. I've found shorts on one chip on the board, on the 2nd ribbon down, only on the top chip. there are 2 pins one end, then 3 more in the middle, and another 3 a bit further along. there is no visible damage to the screen. the SU board looks newer than the others. i suppose the panel is bad, but i wonder why the shorts would all be on one chip. if it is an area of the panel that's damaged, would it not likely take out the chip below too? i think the pins are connected to the chips in between each other, so it seems a bit of a coincidence they are all on one chip, with none on the one below it. i guess there's no way to test the panel itself. should i try replacing the SU board or scrap the set?

[efwiofoi]

Re: Panasonic th-42pz70ba SU board or panel

i think it is the SD board that is newer not the SU board. SD is marked EL1119E and all the other boards inc SU are marked EZ with smaller letters (these are black ink numbers stamped on them). it definitely points to the lower SD board having been changed not SU. the lower part of the panel, with SD connected to it is working. are these boards known to fail without it being caused by the panel? i am leaning towards getting a SU board now and trying it.

[efwiofoi]

Re: Panasonic th-42pz70ba SU board or panel

i've bought a new board as it was only £12 so will check it for shorts first then see what happens.

[efwiofoi]

Re: Panasonic th-42pz70ba SU board or panel

i now have the new board and the tv powers up to this:



there were no shorts on the board. on the old one, the shorts were in the 2nd band to the top. ive tried reseating the connectors but no luck.

is this a faulty board, bad connections , fault panel?

thanks

[tw2005]

Re: Panasonic th-42pz70ba SU board or panel

Can you take some close ups of the ribbons going into the connectors on the SU board. Seating them in properly can be tricky. Even though you've tried reseating them, it took me a few goes on my 2010 model to get them right, I'm use to it now and can do it first go but I found that you feel a little resistance inserting but then with a littl more of a push they would go in a bit further with more resistance present.

I think msot Panasonics have the same style of connector, but you do have some rather large blacked areas. I found misseat you'd get lines and maybe some thicker lines.

Obviously don't reseat with power on. Could be SU or even SC?

I think the ribbons may have a marker or little notches in the sides to help work out if they are in and straight.

Maybe compare these to the ribbons on the SD when installed and see if there are any obvious misalignments.

[tom66]

Re: Panasonic th-42pz70ba SU board or panel

It's very difficult to line up the ribbons on these. Basically they have two positions. One wrong way and one which gives you a little "click" when inserted. You want the "click" one.

If you do find the new SU to fry, the panel is probably bad and scrap. If you decide to get rid of it, let me know, as I have a theory on bad Panasonic plasma panels that I want to test, regarding trying to "clear" a short in the panel with a high current. I'll buy it off you.

[tw2005]

Re: Panasonic th-42pz70ba SU board or panel

Something else i thought of, they have a lever action connector, if the ribbon is not all the way in they can sometimes sit up a whisker and not go all the way down. It won't be much but if the lever is springy and be pushed down and it springs back a little they are not in properly.

The lever will go all the way home when they're correct, I discovered this when i was trying to get it right, not always obvious at a glance.

[efwiofoi]

Re: Panasonic th-42pz70ba SU board or panel

i finally got the ribbons seated correcty



picture came on perfect, for about 10 minutes then click and its gone dead. 7 flashes from the led.

i suspect the screen has fried the new board?

[efwiofoi]

Re: Panasonic th-42pz70ba SU board or panel

there's now a short on the very last pin on the same connector that was shorted before. not the same pin but about 2 away from where it has gone on the other one.

just when i thought it was fixed!

[tw2005]

Re: Panasonic th-42pz70ba SU board or panel

That's a shame, I can only assume the panel has an issue? Such a clear picture too. At least you worked out the ribbons.

I have no fresh ideas for you sorry.

[tw2005]

Re: Panasonic th-42pz70ba SU board or panel

No signs of damage on the ribbon, like a lifted track and shorting there? Not something I've experienced.

[efwiofoi]

Re: Panasonic th-42pz70ba SU board or panel

looks like i might have to scrap it unfortunately. the pic was good while it lasted.
the only thing i was wondering, i didnt check the voltages, Vsus, etc, if one of these was too high, could it cause the short?