Panasonic Th 50PX70B 12 Blinks

[onpiopah]

Hi, and thanks for any help before I begin.
My plasma has 12 blinking red LED flashes and will not start up. I ave managed to source the service manual which is very informative, and leads me to believe the P board is defective.

I am not happy about just replacing the board on the off chance it is faulty and would like to know if anyone would have an idea about what could be wrong with the P board.

Is it worth me trying to locate the problem or am I really wasting my time. I am hoping there is a common fix I can do, surely there is a component that normally fails - or is that too simple.

Thanks again for any help.

[ryan74]

Re: Panasonic Th 50PX70B 12 Blinks

Start by looking close at the power board for any visible bad parts like capacitors that are buldged on top, burnt parts or spots. If you have a volt meter check voltages at connections and post them. If your lucky the board will have most voltages printed on it.

[tw2005]

Re: Panasonic Th 50PX70B 12 Blinks

I think it's both worth your time and significantly cheaper than buying a board. (deleted )



Edit: Sorry , Looks like your board is not be what I thought it was? ETXMM655MEH?

(I intially thought it was the same as the 42PX70 with blown FET Q406, F401,402, + open 5W Resistor, service tip doc below)

Post a picture of the board

Maybe this is the model that has those vertical modules faulty but I thought that was 2 or 10 blink?

[onpiopah]

Re: Panasonic Th 50PX70B 12 Blinks

Thanks that gives me somewhere to start - I'll post a pic and start with testing the Caps and checking voltages.

[tw2005]

Re: Panasonic Th 50PX70B 12 Blinks

For info. Generally electrolytics in the panasonics are ok due to the brands they use.

[onpiopah]

Re: Panasonic Th 50PX70B 12 Blinks

Hi

I have uploaded an image of the board. I will try and test all the voltages today and post the values.

[onpiopah]

Re: Panasonic Th 50PX70B 12 Blinks

I have tested the voltages on the power board and I have attached a schematic of what the voltages should be. Does this shed any light on the cause.

I will take the board off unless someone says otherwise and test all the caps.

thanks for your time.
P12 -
pin 10 has 5v with the AC cord plugged in

when power button pressed -
pin 10 and Pin 8 have 3.5v

PA7
nothing until power button pressed then

pin 5 has 5v
pin 7 has 3.2 v

however there will be a spike of 15v on pin 1 for a second after the power button is pressed in.

PA25
pin 9 has 5v when power button pressed on

[tw2005]

Re: Panasonic Th 50PX70B 12 Blinks

Have you had a go at the 12 blink fault finding flowchart in the troubleshooting guide?

At the very end it asks if you see 15V just before shutdown and if so eliminates the P board then points to D board. But there's a number of other steps first and looks like some isolation and jumpering of certain connectors.

I've never done any of these steps before so i can't talk from experience.

[onpiopah]

Re: Panasonic Th 50PX70B 12 Blinks

Hi thanks for your reply.

i did go through the fault finding and I kept ending up with advice on either to change the power or the D board.

they were a little inconclusive because even though the service manual is for my specific Plasma (and a few other models) there is a slight difference in the models and the fault finding did not 100% adjust for this.

I think it is either the p or D board - its where to go from there. Just replacing either of them seems to be giving up and probably more expensive than the plasma is worth.

[tw2005]

Re: Panasonic Th 50PX70B 12 Blinks

Don't know if you've read this.

[tom66]

Re: Panasonic Th 50PX70B 12 Blinks

I noticed you're not too far from me. I hope you can fix this one, but if you can't, then I will offer to buy it from you, as it would be a shame to see it thrown out.
Check my signature for many Panasonic service manuals and training guides.

[JonathanAnon]

Re: Panasonic Th 50PX70B 12 Blinks

Is there something odd looking about the main fuse F602.. I think it looks burnt.. I know it must be working given that there are voltages on some of the rails but it looks burnt on one side.. The two large caps C257 and C256 look slightly bulged and might be worth testing... Cant see anything else that looks dodgy..

I like the way you've marked half of the pots to show where they have been moved to.. I usually mark them with one dot but even still it can be hard to keep track of how far they have been turned.

[tom66]

Re: Panasonic Th 50PX70B 12 Blinks

Looks like factory markings to me...

[onpiopah]

Re: Panasonic Th 50PX70B 12 Blinks

Hi - no fuses are fine, which is a shame. the markings are from a marker pen, and do seem to be from the factory.

I was looking at a small capacitor and it reads

0.01 Uf on the casing but tests at 5400 pf

is that an acceptable range?

[tom66]

Re: Panasonic Th 50PX70B 12 Blinks

0.01uF = 10nF != 5.4nF
Could be something wrong there, then.

However, if you are measuring in circuit, then it could be misleading you, you would need to remove it to be sure.

[onpiopah]

Re: Panasonic Th 50PX70B 12 Blinks

Hi,

I am measuring out of circuit. I know the value should be 10,000pf and not 5400 but is it far enough out to cause such a major problem.

this is the capacitor

http://www.digikey.co.uk/product-sea...yRIR&network=g

Could i replace it with one of these

http://www.maplin.co.uk/polyester-la...s-353#overview

in a 0.01uf

[tom66]

Re: Panasonic Th 50PX70B 12 Blinks

If that's on the AC input, it's unlikely -- those capacitors do tend to fall in value with age. But they're only used for filtering out the AC line noise the plasma kicks back into the mains.

If that cap is rated to 275VAC or higher, that Maplin one should be fine.

[onpiopah]

Re: Panasonic Th 50PX70B 12 Blinks

Thanks I'll keeping looking, and change that cap anyway.

Could take me a few months to test every piece on the board -

I was thinking of doing all the caps first

then the transformers

would anyone disagree, are parts more suspect than others??

[JonathanAnon]

Re: Panasonic Th 50PX70B 12 Blinks

http://www.tgohome.com/ServiceManual...PX75U_[SM].pdf

There's a schematic of that same ETXMM655MEH power supply in this service manual for a similar type of TV. This will help you to troubleshoot the components..

If it was me, I would start by printing out the P-board schematic and take note of what voltages are on all the connections. You can then establish which parts are working and which are not, then focus your troubleshooting on the components on those sections..

There are a lot of "Power Control" and "Control Module" ICs on the board, I'm not sure how you are gonna be able to check those, aside from checking the similar ICs against each other.

[onpiopah]

Re: Panasonic Th 50PX70B 12 Blinks

Cheers, I am hoping I will touch lucky early on.