Panasonic TX-P42C2l : No Power with 4 LED Blinks

[bigbadtom]

hi i have this issue with panasonic tv.

read in other post about disconnecting the sc and ss board and SOS light should change but didn't change

looked for obvious problem like caps on all board but cant see anything that is obviously shorted

anybody any advice for me

mechanical engineer slight electronic experience but not enough

thanks guys

[tom66]

Re: Panasonic TX-P42C2l : No Power with 4 LED Blinks

Could you perhaps supply pictures of the parts inside the TV, and one of the whole TV with the cover off? So we can see what we are dealing with.

[bigbadtom]

Re: Panasonic TX-P42C2l : No Power with 4 LED Blinks

Please see attached any help gratefully accepted

[tom66]

Re: Panasonic TX-P42C2l : No Power with 4 LED Blinks

Ok, so in the condition there you still have the SS connected to the P board. Have you tried disconnecting that and powering the TV up again?

[bigbadtom]

Re: Panasonic TX-P42C2l : No Power with 4 LED Blinks

disconnected the ss board. and sc board at same time light changed to six blinks
reconnected the sc board without ss connected and went to seven

[tom66]

Re: Panasonic TX-P42C2l : No Power with 4 LED Blinks

Ok, can you try the set with the SC and SS connected again and verify you are back to 4 blinks. And when you have the SS disconnected could you check that it is definitely 7 blinks you see and not 8.

[bigbadtom]

Re: Panasonic TX-P42C2l : No Power with 4 LED Blinks

Both boards connected it's 4

yes with ss board ( the one to top right in pic) disconnected and the sc connected it's 7

[tom66]

Re: Panasonic TX-P42C2l : No Power with 4 LED Blinks

Ok, my guess would be the SS board is shorted. Can you remove the board and get clear photos of the top and bottom of the board? Do you have a digital multimeter available?

[bigbadtom]

Re: Panasonic TX-P42C2l : No Power with 4 LED Blinks

removed board hope you can see I found issue all eight same component have blown one of its legs.

solution is to buy second board?
but what caused it may cause it again?

[tw2005]

Re: Panasonic TX-P42C2l : No Power with 4 LED Blinks

If you can't find a board, I've had success repairing these by replacing the 4 RJP30E4 transistors. The M817135FP FET driver seems to survive although not a bad idea to replace it.

easiest way to remove the transistors is either snip the legs close to the body without twising them or the track will tear or heat the solder and lift each leg whilst the solder is molten. Then you tin the meatl tab and heat until it bubbles and get the body off. I get away with a 40w iron and medium tip.

I did have one board I used fail again after a few days. Not sure why, I got the parts from china so maybe that but my second bpoard I had a 50" board I stripped the transistors from that and that has been fine, also I replaced the FET driver. The first one I did not, again possibility.

Glad I asked what model you had, kind of makes a big difference with the answers you get.

The SS failure in these is very common but it can also take out the SN board, hopefully you had SS3 disconnected when you powered up isolating the SS.

May pay to bell out the large transistors on the SN too. There's a couple of SMD diodes that can blow too, D441,452.

[tw2005]

Re: Panasonic TX-P42C2l : No Power with 4 LED Blinks

Make sure you get the correct revision board or else it won't connect to the ribbons. There is an alternate fitted to some US Sanyos with the same panel. these are starting to get scarce and more expensive

[bigbadtom]

Re: Panasonic TX-P42C2l : No Power with 4 LED Blinks

Think I have one for 75 euro not too bad. hope it doesn't blow. as regard to getting the sos three didn't happen at0any stage.
wonder why not.
not very electronically experienced so think will take hit on board and hope for best
you agree?

[tw2005]

Re: Panasonic TX-P42C2l : No Power with 4 LED Blinks

Think I have one for 75 euro not too bad. hope it doesn't blow. as regard to getting the sos three didn't happen at0any stage.
wonder why not.
not very electronically experienced so think will take hit on board and hope for best
you agree?

No, SS3 = connector SS3 on SS that connects to SN3 (SN board)

Ouch. What does 75 euro translate to GBP? That would be $110 AUD for me

You might get some change back for the old board selling it. Somebody may like to repair it. cheap repair parts wise.

[tom66]

Re: Panasonic TX-P42C2l : No Power with 4 LED Blinks

When you say blown off the leg... you're not talking about the stub leg right? That is normal for those devices.

You should check if they are shorted with a multimeter.

[tw2005]

Re: Panasonic TX-P42C2l : No Power with 4 LED Blinks

I'd still be checking out the SN as a precaution. I have read a post where a new board got killed by another and they went around in circles for a bit. Would have to do a search. Going back a bit now.

[tw2005]

Re: Panasonic TX-P42C2l : No Power with 4 LED Blinks

It was this one I think. https://www.badcaps.net/forum/showth...npa5072&page=2

the way I read it , SOS 4 cleared with new SS, (no SN) after everything hooked up he ended up with another fault, then somehow ended up with shorted SS again so I'm presuming his SN was damaged also and killed the SS again.

Just something to be aware of as there is an assumption the SN is still good at this point.

[bigbadtom]

Re: Panasonic TX-P42C2l : No Power with 4 LED Blinks

Have to leave it for tonight unfortunately.
tw2005 you mind if I give you private messagage tomorrow?

[tw2005]

Re: Panasonic TX-P42C2l : No Power with 4 LED Blinks

Have to leave it for tonight unfortunately.
tw2005 you mind if I give you private messagage tomorrow?

If you feel it's necessary, nothing wrong with keeping it posted here.

I'm just jumping in because I have the same Tv and also some spare working boards to check stuff + I've made some mistakes and popped the Sn twice now fault finding it.

[bigbadtom]

Re: Panasonic TX-P42C2l : No Power with 4 LED Blinks

Not sure if my multimeter read transitors maybe just solder legs and cross fingers

[tom66]

Re: Panasonic TX-P42C2l : No Power with 4 LED Blinks

You can check for shorted transistors with the diode or 200 ohm range of your multimeter. Just check across all pin combinations of the transistor.