Panasonic TX-P42U30B green light flashes no picture

[Andyd1970]

Hi Guys,

Just bought a Panasonic TX-P42U30B to be used in the bedroom from a guy for £40.00 as not working. Basically you power it up you hear a relay clicking a few times the green light flashes and then nothing. I was hoping bad caps but when I stripped it they all seem OK.

So I started to check for voltages, I put one probe onto the chassis and checked for voltages coming from bottom right connector on PSU to main PCB and the top left and top right connectors on PSU going to the inverters? (I guess it cant have two inverter PCB's). All I was getting was MV.

I have a digitial meter happy to recheck voltages etc.


Help Andy

[tom66]

Re: Panasonic TX-P42U30B green light flashes no picture

It's most likely an A board fault.

[Andyd1970]

Re: Panasonic TX-P42U30B green light flashes no picture

HI Tom, Which board is the A board please?

[tom66]

Re: Panasonic TX-P42U30B green light flashes no picture

The one with the video inputs on it.

[Andyd1970]

Re: Panasonic TX-P42U30B green light flashes no picture

OK, Is there a way to prove it? would it be wise to remove connectors etc and check voltages?

Andy

[tom66]

Re: Panasonic TX-P42U30B green light flashes no picture

Unplug SC power: should go to 6/7 blinks.
Reconnect SC, Unplug SS: should go to 8 blinks.

That eliminates the sustain boards, but doesn't totally rule out another board causing issues. If no error codes fire up it's most likely an A board fault.

[Andyd1970]

Re: Panasonic TX-P42U30B green light flashes no picture

Hi Tom, Which PCB is SC and SS ?

Andy

[tom66]

Re: Panasonic TX-P42U30B green light flashes no picture

SC = SN on this, left of screen connected to panel ribbons.
SS = right of screen connected to panel ribbons.
Do not unplug panel ribbons or white flex cable.

[sordids999]

Re: Panasonic TX-P42U30B green light flashes no picture

might be buying this tonight displays 6 flashing lights when you try to turn it on any ideas read it could be a possible SC BOARD ?

thanks

[tom66]

Re: Panasonic TX-P42U30B green light flashes no picture

SC or A board in most cases.

[sordids999]

Re: Panasonic TX-P42U30B green light flashes no picture

ok tom thanks ill post some pictures later if i get it

[1967tux]

Re: Panasonic TX-P42U30B green light flashes no picture

hi tom i have the same problem but green light stays on unpluged sn 7 blinks but when i unpluged ss no change does this mean faulty ss board?

[tom66]

Re: Panasonic TX-P42U30B green light flashes no picture

Probably SN, check for shorted IGBTs/FETs.

[1967tux]

Re: Panasonic TX-P42U30B green light flashes no picture

hi tom sorry when i unplug the ss when i say no change i meant the i get the green light just staying on no but not the 8 blink fault code.

[newtothis]

Re: Panasonic TX-P42U30B green light flashes no picture

Aha same internals as the one I am currently working on!

[1967tux]

Re: Panasonic TX-P42U30B green light flashes no picture

sorted this one now faulty ss board had shorted IGBTs/FETs. sent off for repair refitted and bingo all up and working! thanks guys for your help

[tw2005]

Re: Panasonic TX-P42U30B green light flashes no picture

sorted this one now faulty ss board had shorted IGBTs/FETs. sent off for repair refitted and bingo all up and working! thanks guys for your help

thanks for the info, any way of tell what parts were replaced besides those igbts? any of the samler stuff touch like small 8 pin driver ics/