Panasonic TX-P42S30B Possible Bad Panel?

[Hamie]

I have this Panasonic Plasma basically it had a bad Y-sus or SC board whatever you want to call it.

Identical to this fault in one of Norcals videos.
https://m.youtube.com/watch?v=uIyHr13b5w8

I checked the sn2 connector for short to ground and it was 0.2ohm.

So I checked q401, q402 q421 and q422
All shorted,

also d401 and d421 and the 4 resistors.
Both d401 and d421 tested fine and the resistors were 7.5ohm as lablled.

So i installed 4 new igbts and powered on the TV. It appeared to work (I didn't have time to check the picture but the screen definitely turned on as I could see the reflection)

But after about 4 seconds it clicked off, now it's back to the 7 blinks again.
I assumed that I must have missed something and checked for shorts, all the parts still test ok and SN2 connector is 2.9M ohms rather than 0.2 so appears to be good.

Anyway I tent to avoid tvs with silly blink codes. So wondering if anyone who's familiar with panasonics might know of any other faults or tests that can be done to determine if the board is working and it's the panel itself causing the fault.

[ReeceyBurger123]

Re: Panasonic TX-P42S30B Possible Bad Panel?

I did one the exact same the other week, there is a small ceramic capacitor that is near the igbts replace that as it goes leaky. If you look on youtube for Maxxarcade he has a video called panasonic plasma tv repair thats fairly recent that shows everything to replace on this board.
Also check that you seated all the ribbon connectors that go to the screen correctly they are very hard to get in properly.

[Hamie]

Re: Panasonic TX-P42S30B Possible Bad Panel?

Cheers I'll check it out.
Pretty sure I had the ribbons in correctly but no harm in reseating them.

[flocko]

Re: Panasonic TX-P42S30B Possible Bad Panel?

Have you checked the DG302s these go leaky some times not all ways short? IC502 and Q531 I have found in 8 out 10 repairs need replacing, and have you checked buffer ICs as these also fail and are hard to replace. I do an exchange repair service for this board on eBay but bo not take exchange if it has been worked on Flocko

[Hamie]

Re: Panasonic TX-P42S30B Possible Bad Panel?

I noticed that both the ic501 and q531 were in a repair kit, but couldn't find a part number to check if they were defective.

I'll check the DG302.

I've checked the IC's by placing probe on ground screw and running other probe down both side of the rails. Didn't get a short.

As i say the TV did power up, for a few seconds. I'll see if ohm supplies will do me a deal on the kit minus the igbts.

[Hamie]

Re: Panasonic TX-P42S30B Possible Bad Panel?

Also the capacitor reecyburger mentioned without a schematic i don't know what the rating is.

[ReeceyBurger123]

Re: Panasonic TX-P42S30B Possible Bad Panel?

Also the capacitor reecyburger mentioned without a schematic i don't know what the rating is.

So did it test bad ?

[flocko]

Re: Panasonic TX-P42S30B Possible Bad Panel?

You will not see short to ground ? you use floating ground for buffer IC testing ? test point TPVFG just above buffer IC4805. IC502+Q531 test to ground all legs should read M ohm or OL any low ohm readings show to be faulty. Did you get green LED alight top right when set powered on ? have you tested all SMD diodes and IGBTs ? with Panasonic boards if you do not get them right first time you will for sure blow other components

[Hamie]

Re: Panasonic TX-P42S30B Possible Bad Panel?

Ok so I've had a bit more time to go over this board.
The bottom buffer has a short.

There's a bunch of smd diodes that are shorted on the "buffer board" section.

any good ways to get the "road tar" off the chips?

[flocko]

Re: Panasonic TX-P42S30B Possible Bad Panel?

that's a pain there are no good ways to get the ICs off let alone the silicon, it goes under the ICs and bonds them to the board. You can try cutting the legs, this is the way TW tried and I think he did get one off clean. you have to make sure not to cut though to deep as the traces go under as well off the sides. And the silicon pulls the pads off as well when you try to remove the body, you can use nail varnish remover to get the silicon softer but it will not help with the underside of the IC let me know how it goes Flocko

[ReeceyBurger123]

Re: Panasonic TX-P42S30B Possible Bad Panel?

Its easier to just buy a new ysus if the buffers are blown, thats a shame because they are expensive.

[Hamie]

Re: Panasonic TX-P42S30B Possible Bad Panel?

To be honest I'd rather try to fix it, learning from mistakes is half the fun!

[ReeceyBurger123]

Re: Panasonic TX-P42S30B Possible Bad Panel?

Fair enough good luck with it let us know how it goes

[flocko]

Re: Panasonic TX-P42S30B Possible Bad Panel?

The ICs you can get from sparedparts trade for under £10 or eBay £12.49 just take your time , they also do the parts for IC502 and Q531. Flocko