Panasonic TH-P42V20A SC fault

[dorz]

Hey guys, first post here but ive done a bit of searching, so much information on this forum it is amazing

my story is pretty similar to the thread below.

got given the tv, fault was 4 blinks - power. VSUS was basically 0v. unplugged SC2, VSUS jumped up to ~200v, and now giving me 7 blinks. unplugging the SC SOS cable gives me 6 blinks.

https://www.badcaps.net/forum/showth...4+blink&page=2

this thread was incredibly helpful, including post 23, which is almost exactly what has happened to my SC board.

i can see IC521 looks to be damaged, has a burn mark on the top of the IC. the SC2 connector pins are almost a dead short, 0.6ohm or something across them. i have removed IC521, still shorted, so i will need to trace the circuit and remove some fets to test them.

couple of questions i have are: what is IC521? it is a mitsubishi M81737FP. what would cause this to pop? does anyone have any tips to troubleshooting these boards?

i cant find the same circuit boards for sale (TNPA5105 for 42"), only the ones for 46" or 50". what are the differences between the boards besides component locations? has anyone tried substituting boards and or components on these SC boards?

is there anywhere in australia i can get a TNPA5105 board without spending a fortune?

Thanks!
Dorz

[tw2005]

Re: Panasonic TH-P42V20A SC fault

Looking at Shopjimmy he has no stock at all. Pretty clear indication to me these fail a lot.

There's a 42" in Canada Ebay $70 postage $96 but he does state to contact him for postage as i'd be surprised if it actually costs this much.

There's also a 7 piece semiconductor replacement kit in UK but $65 so I would find a board unless you can be sure everything else is good otherwise you may end up with still a dead board and empty wallet.
It covers Q421/Q422/Q451/Q401/Q402/Q661/D482

i think those ic are driver chips which I have 2 on my dead 50" board but i think you will find a lot of shorted Transistors and diodes which are the cause.

there's also a 46" board which looks closer to the 42 but unless you can find service manuals for the 42 and 46 to compare components and voltage settings it would be a bit of a guess.

[dorz]

Re: Panasonic TH-P42V20A SC fault

Thanks for your advice TW2005

i will have a look to see whether the boards are interchangable, hopefully they are.

will contact the ebay seller too, thanks so much for your time finding that for me!

Dorz

[freakaftr8]

Re: Panasonic TH-P42V20A SC fault

Look for a shorted Zener diode in the circuit of the blown MOSFET.

[dorz]

Re: Panasonic TH-P42V20A SC fault

had a poke around then, couldnt find any shorted zeners around there. i might pull off a couple of fets later today if i get time hopefully i can find the fault via elimination, i will have to check the ic to make sure it is definitely blown too.

[ryan74]

Re: Panasonic TH-P42V20A SC fault

im working on a panasonic TC-P42U1
many boards were advertised as TNPA4829 so i ordered one

barcode sticker on my sc board said TNPA4829AD
the board i recieved was TNPA4829AB

the connections to SD/SU boards were different so BEWARE you may need exact replacment. I even emailed the seller before shipment to verify the correct part and he still sent the wrong one.
I think i ordered the correct one now but it cost me $90

[tw2005]

Re: Panasonic TH-P42V20A SC fault

im working on a panasonic TC-P42U1
many boards were advertised as TNPA4829 so i ordered one

barcode sticker on my sc board said TNPA4829AD
the board i recieved was TNPA4829AB

the connections to SD/SU boards were different so BEWARE you may need exact replacment. I even emailed the seller before shipment to verify the correct part and he still sent the wrong one.
I think i ordered the correct one now but it cost me $90

That's a good tip. something easily missed.

Do you think you could have desoldered and swapped the connectors from your original?


Board layout looks the same. Also where TPVAD is, the 7 pin powerchip does yours have a heatsink and the wrong one not?

[dorz]

Re: Panasonic TH-P42V20A SC fault

no mine doesnt have a heatsink... not sure if you're referring to me or ryan though.

as far as i can see, the only different components between the 42, 46 and 50" boards are the location of a couple of coils (L401,2,3, L411,2,3). connectors look the same,and in the same places. i might bite the bullet and try this one out with a 46" board... the SC boards do only supply the power to the panel doesnt it, not control the pixels?

[tw2005]

Re: Panasonic TH-P42V20A SC fault

no mine doesnt have a heatsink... not sure if you're referring to me or ryan though.

as far as i can see, the only different components between the 42, 46 and 50" boards are the location of a couple of coils (L401,2,3, L411,2,3). connectors look the same,and in the same places. i might bite the bullet and try this one out with a 46" board... the SC boards do only supply the power to the panel doesnt it, not control the pixels?

No, It was off topic a bit and to Ryan hence the quote.

I think there's more than just the coils. Capacitors and also they may use different transistors in the same locations or even additional ones in vacant spots. Have a closer look at the 50" board and you should see what I mean.

I downloaded 42 and 46 service manuals but found out it was updated to the new SN boards which incorporates the buffers and SC all in one so no good for comparison.

Was the Canadian board too expensive with freight?

[tw2005]

Re: Panasonic TH-P42V20A SC fault

Try downloading this. My connection dropped out so it won't let me download again today. Hopefully it has a SC board.

At least you will have schematics,layouts and you could go to the parts listing and compare whats used on each board.

Huge task though.

If you go for the 46 then you will be a pioneer I feel.

i've attached the 46" manual.

[dorz]

Re: Panasonic TH-P42V20A SC fault

thanks heaps Tw2005, downloading now.

ill have a gander

i didnt manage to find the canadian board on ebay.ca, have you got a link for it? my searches only pull up the 4 from us/uk from the 'international sellers'

cheers!

[tw2005]

Re: Panasonic TH-P42V20A SC fault

thanks heaps Tw2005, downloading now.

ill have a gander

i didnt manage to find the canadian board on ebay.ca, have you got a link for it? my searches only pull up the 4 from us/uk from the 'international sellers'

cheers!

Did you tick the check box, include description? Always helps to dig up more in the search.

It's Rev AD which I suspect yours is.
Says it was purchased from Shopjimmy so good chance it's fairly new pulled from damaged in Transit new TV.

Would not hurt to pick the guys brains for his fault as he states he bought it thinking it was SC but eneded up being A-board.

But yours does sound like the same fault as mine for SOS4.

http://www.ebay.com.au/itm/Panasonic...item2324ebafda

Hope you don't miss out on it. You may have to just cop whatever the cost is given the rarity of these parts. Still much cheaper than getting new here or paying someone to fix.

[tw2005]

Re: Panasonic TH-P42V20A SC fault

Buy it! It should cost SFA. He's quoting Canada Express international(probably an Ebay built in calculator)

Options range from Small Packet-Int'l Surface $17 (4-6 weeks), Small packet-Int'l Air $39 (6-10 business days) and it goes up from there.

Me personally would opt for small Air unless you don't mind waiting forever. I'd stipulate to the the seller which option exactly you want. he does say choose your own.

http://www.canadapost.ca/cpotools/ap...execution=e1s2

Good Luck.

[dorz]

Re: Panasonic TH-P42V20A SC fault

contacting him now, he is changing it for me to the small packet air

thanks so much for your help TW2005. where in australia are you?

[tw2005]

Re: Panasonic TH-P42V20A SC fault

contacting him now, he is changing it for me to the small packet air

thanks so much for your help TW2005. where in australia are you?

Newcastle but not for long , Darwin 2013

[ryan74]

Re: Panasonic TH-P42V20A SC fault

That's a good tip. something easily missed.

Do you think you could have desoldered and swapped the connectors from your original?


Board layout looks the same. Also where TPVAD is, the 7 pin powerchip does yours have a heatsink and the wrong one not?

I could have swapped them but there were other differences
Heatsinks all matched
Adjustment pot missing
1 less capacitor

[tw2005]

Re: Panasonic TH-P42V20A SC fault

I could have swapped them but there were other differences
Heatsinks all matched
Adjustment pot missing
1 less capacitor

Blind as a bat. I did miss all those.