panasonic tx42-p42x20b

[adamp91gvm]

Re: panasonic tx42-p42x20b

The 3.1v is there till it clicked the second time then it goes to 0v

[adamp91gvm]

Re: panasonic tx42-p42x20b

Yer it will be 11 to 1 then

[adamp91gvm]

Re: panasonic tx42-p42x20b

I think I'll try find a a-board or a broke screen on but that model is really hard to find is there any other model with the same a board?

[tw2005]

Re: panasonic tx42-p42x20b

You may find that the same A board is used across the range for all the different sized X20B models but the firmware will be different for each size.

It is possible to do a EEPROM swap from your board to another tomake it a 42" board but we'd have to assume they are good still.

I've done it to convert from a New Zealand X20Z to an Aussie X20A. NZ and Aust have different frequency standards. It worked but except I had image issues which I donot know if they are A board related or not. The TV was a mess as it had bad SS,SN,C & A which i component level repaired so part of that could be my doing.

For yours it may only be 1 eeprom to swap.

I don't quite understand why the US boards i listed would not suit? For me a board with the same appearance, same PCB number and the same revision suffix should in fact be an identical part?

It'd be nice to continue to fault find the A and see if it is possible to nut it out down to a component. I'm not sure i can do that for you, not something I've gone too deep into before.

I'd be curious to see what those sub voltages measure.

[adamp91gvm]

Re: panasonic tx42-p42x20b

I might spend a bit of time on it see where I get to thank you again for your help

[tw2005]

Re: panasonic tx42-p42x20b

I'm actually starting to think the TX-P42X20B is not a US model at all but somehow SJ has the parts. I only get UK hits for it and the US Panasonic site does not recognise that model.

The antenna socket does not even look like a typical US connection. This is only a guess but maybe they were in transit in the US and damaged there so that's where they were written off.

Maybe they got the opportunity to get them cheap. They ship worldwide so why not . I was chatting online a while back and the guy suggested SJ was considering setting up in the UK too. But that's hearsay.


It might be worth asking the question if they suit UK but If it's the price you don't like I can understand that with freight .

[adamp91gvm]

Re: panasonic tx42-p42x20b

I know it seems a dumb question but where would I test the sub voltages on the A board I'm at the tv now

[tw2005]

Re: panasonic tx42-p42x20b

I might spend a bit of time on it see where I get to thank you again for your help

Well you have the schematics etc so why not. You could resistance check those sub voltage lines and see if shorted. You have a clue that the SD slot was related to it shutting down whether that be 100% true or not but that may point back along the 3.3V which that IC I mentioned also regulates the 5V which i reckon it will be the voltage that's wrong if I was to have a guess.

If the 5V is shorted, determining which device would be hard as there will be several things all running off the 5V. may even be something simple like a fusible link on the board being open. That's where the schematic might help.

[tw2005]

Re: panasonic tx42-p42x20b

I know it seems a dumb question but where would I test the sub voltages on the A board I'm at the tv now

Open the manual in PDF, look at P61, identify the SUB voltages, there are points labelled as TPxxxx. They're test points but you could follow the cct and pick any point or item the SUB5V feeds for example. use the search function.

e.g. if you put TP5603 in the search it will take you to P82 and shows it on the A board on the foil side or underside which is a pain as you don't want the board flopping around unbolted possibly damaging ribbon cables or shorting on the chassis.

So search sub5V and see where it feeds on the board.

Either side of L5605 on topside for 5v

L5604 for 3.3V

Search sub9v,sub5v.

I have to get a few more winks of sleep, I woke up and jumped on here for a bit.

have fun.

[tw2005]

Re: panasonic tx42-p42x20b

I've never tried checking these voltages myself but I suspect once the 10 blinks starts the A board will stop trying to generate them so thye may only be present on startup meaning you'll have to keep cycling the TV on for each test point.

Hopefully if anyone else out there knows more about the A board they'll chip in with some info too.

[Hombre]

Re: panasonic tx42-p42x20b

Well i had 10 blinks problem on my TX-42PY85 and it turned out that was the a board problem. It was shorted one of sub voltages, i think it was 3.3v but not sure ), shorted ceramic capacitor caused that. 15v read ok on p6 connector but it wasn't even going to the dc dc converters because due to short the 5 amps fuse blew .
So, listen to the Panasonic master aka tw2005 and look for shorts on that sub voltages

[adamp91gvm]

Re: panasonic tx42-p42x20b

im really new to all this i get lost in translation at the moment im really sorry u guys and i really appreciate all your help but i get lost when things like sub voltage comes into it im slowly learning. how would I read the sub voltages tw2005 has allready been a huge help

[adamp91gvm]

Re: panasonic tx42-p42x20b

i have the schmatic diagram just looking at it now trying to understand it

[adamp91gvm]

Re: panasonic tx42-p42x20b

Right don't know if I'm right here but on cn0101 as I look at it top left connector that is not connected to any thing I get 3.3 v?

[vinceroger69]

Re: panasonic tx42-p42x20b

out of curiosity has your psu got one of these transformers on?
http://www.youtube.com/watch?v=qQ_iLxx3Fj4

[adamp91gvm]

Re: panasonic tx42-p42x20b

No its only got smaller ones

[adamp91gvm]

Re: panasonic tx42-p42x20b

Right been over the board and there is no power at all to the top ribbon a20 I'm getting 4.5v into the chip under the heat sink but noting coming out ...

[tw2005]

Re: panasonic tx42-p42x20b

Right been over the board and there is no power at all to the top ribbon a20 I'm getting 4.5v into the chip under the heat sink but noting coming out ...

A20 feeds the SN board, only voltages there are 5V & 15V.I suspect 15V won't be generated unless those sub voltages are produced first and it gets past SOS10. The 5V should be there though, if not it just brings us back to what we already suspect. Problem with the SUB 3.3/5V.

Did you locate those inductors? there's probably easier points . Measure resistance to ground for both of those see if either are really low.

[tw2005]

Re: panasonic tx42-p42x20b

Right been over the board and there is no power at all to the top ribbon a20 I'm getting 4.5v into the chip under the heat sink but noting coming out ...

What chip? What heatsink? give me a clue. Photo/part number/location ID eg ICxxx?

[tw2005]

Re: panasonic tx42-p42x20b

Right don't know if I'm right here but on cn0101 as I look at it top left connector that is not connected to any thing I get 3.3 v?

Took me a little while to digest this but did you mean CN0102 pin 1?

Should be STDBY 5V there. 3.3V is low for 5V

CN0101 is the unpopulated 20 pin pad above it.

You already reported 4.8V for STB5V at pin 1 of P7, same voltage should be at pin 1 CN0102.