Panasonic Plasma TV LED blinking 12 times

[tw2005]

Re: Panasonic Plasma TV LED blinking 12 times

The voltage increases gradually over a couple of seconds and reaches a max of 1.56v which is steady for probably about a second then shuts off. Will do the test again and take better note of what happens. tw2005 I agree with what you are saying, I'll check out Q2301.
I did identify the FET as 25K2510, I just can't seem to find a data sheet for it to see it's spec in case it is faulty and need to find an equivalent.
Thanks for the help guys.

if you keep typing 25K2510 when it's 2SK2510, you won't. i get a page full of hits, the first being a spec sheet.

One would think if it takes 2 secs to get to 1.56v, holds for a sec then shutdown, PSU fault is looking likely.

Did a quick search here for equivalents http://alltransistors.com/mosfet/crs...024&caps=MP45F

2SK2498, 2SK2512

Type Designator: 2SK2510

Type of 2SK2510 transistor: MOSFET

Type of control channel: N -Channel

Maximum power dissipation (Pd), W: 35

Maximum drain-source voltage |Uds|, V: 60

Maximum drain current |Id|, A: 40

Maximum junction temperature (Tj), °C: 150

Maximum drain-source on-state resistance (Rds), Ohm: 0.024

Package: MP45F

[PaulF]

Re: Panasonic Plasma TV LED blinking 12 times

Doh,
Sorry, will have to get some glasses. even when I saw it in your message I read it as 5 instead of S. Good job there is someone around to put me right.

[tw2005]

Re: Panasonic Plasma TV LED blinking 12 times

Doh,
Sorry, will have to get some glasses. even when I saw it in your message I read it as 5 instead of S. Good job there is someone around to put me right.

I stopped short of suggesting that, all I know is once you have them , they never seem strong enough.

Don't worry, someone else would have pointed it out. The fact 2 of us posted 2SK2510, you had me wondering especially with the , can't find the datasheet comment.

[PaulF]

Re: Panasonic Plasma TV LED blinking 12 times

TP2302 does indeed go high to flag the SOS.
I nonitored the G-S voltage of mosfet Q351 with a scope, this never rose above a fraction of a volt during switch on & just looked like noise. This obviousy isn't sufficient to turn the device on hence 15v at D and no 15v at D.
I then monitored pin 4 of MC351 which is marked 15V_ON, which i assume is the signal to turn Q351 on, this remained constantly 0. This in turn comes from MC701.
I am probably at the point now where I am beginning to condider that I'll have to replace the power board, unless anyone has any suggestions.

[PaulF]

Re: Panasonic Plasma TV LED blinking 12 times

Typo: Should have been 15v at D and no 15v at S

[tw2005]

Re: Panasonic Plasma TV LED blinking 12 times

No real idea, just wild guesses. Is there 15V at pin 8 of MC701 . Micro fuse IP351 on the underside, ?

[PaulF]

Re: Panasonic Plasma TV LED blinking 12 times

You could be on to something there. Just checked pin 8 of MC701 and it gets up to 3.2v only. Will lift the board out and check IP351 as you suggested.

[PaulF]

Re: Panasonic Plasma TV LED blinking 12 times

Just studied tthe diagram again. I have 15v at TP7. Between pin 8 of MC701 and TP7 are: R367, R351 and and unidentified symbol. Will check through that part of circuit.

[tw2005]

Re: Panasonic Plasma TV LED blinking 12 times

I don't think IP351 is the fuse for the 15V in on pin 8 but the diagrams seem to suggest some kind of fuse for that, I can't get my head around it. But if you got 15V at TP7 then that passes through what appears to be a fuse, then R351 10.5K, then R367 10k then pin 8 so not sure if 15V_in means 15V should be at pin 8 or not to be honest.

looking at p65, T301, S4a.

[tw2005]

Re: Panasonic Plasma TV LED blinking 12 times

Just studied tthe diagram again. I have 15v at TP7. Between pin 8 of MC701 and TP7 are: R367, R351 and and unidentified symbol. Will check through that part of circuit.

LOL, Something tells me you understand this better than I

[PaulF]

Re: Panasonic Plasma TV LED blinking 12 times

I think pin 8 of MC701 is the sensing signal for the 15v supply so what I measured could be correct.
It seems like MC701 is not giving the signal to turn on the 15v to the H board, wether thats due to a fault on MC701 or due to it thinking there is a fault elswhere is difficult to know.
Without knowing what all the pins should read it could be difficult to know if things are right or wrong.
I'll have to decide if it's worth risking buying another P board (I've located one for about £60) or havee a trip to the local tip. I don't mind buying the new board if I'm sure that's where the fault is.
Thanks for all the help.

[tw2005]

Re: Panasonic Plasma TV LED blinking 12 times

I think pin 8 of MC701 is the sensing signal for the 15v supply so what I measured could be correct.
It seems like MC701 is not giving the signal to turn on the 15v to the H board, wether thats due to a fault on MC701 or due to it thinking there is a fault elswhere is difficult to know.
Without knowing what all the pins should read it could be difficult to know if things are right or wrong.
I'll have to decide if it's worth risking buying another P board (I've located one for about £60) or havee a trip to the local tip. I don't mind buying the new board if I'm sure that's where the fault is.
Thanks for all the help.

yeah , I had a bit more of a look and I was starting to think the same, with 15V_in, 15V_on,15V_out and those resistors the likelihood of 15V meant to be there was looking slim. So I was half expecting you to come back with that.

I was guessing, when you said 3.2V , a logic high crossed my mind.

makes me wonder if 3V was injected into MC351 pin 4 what would happen?

I know what you mean, getting a PSU and still having the fault would annoy me too if that happened.

Anyway you never know, someone might come up with something. It'd be great if you knew someone with the same TV/ PSU for a quick swap/test.

ETXMM655MEH

[PaulF]

Re: Panasonic Plasma TV LED blinking 12 times

I was thinking along the same lines as you abou injecting a voltage into MC351 pin 4 but was a bit nervous of doing it in case the reason for it being absent at the moment was for protection due to a fault elsewhere, if I inject a voltage I could cause more damage.

[PaulF]

Re: Panasonic Plasma TV LED blinking 12 times

Success.
I fitted a replacement P board and it's all working again.
Shame I replaced the H and DG boards first. I put the originals back in so if anyone needs a H or GD board, let me know.
All the best to all on the Forum who helped to diagnose the problem.

[tw2005]

Re: Panasonic Plasma TV LED blinking 12 times

Success.
I fitted a replacement P board and it's all working again.
Shame I replaced the H and DG boards first. I put the originals back in so if anyone needs a H or GD board, let me know.
All the best to all on the Forum who helped to diagnose the problem.

Good to hear, shame we did not nail it to a component.

[EIEIO]

Re: Panasonic Plasma TV LED blinking 12 times

PaulF, I'm glad to hear you fixed your TV. (Sorry to hijack your thread earlier, but I was new to this forum and couldn't start my own).

I have different boards on my TC-P42S1 tv, but tried the same as you as suggested in the documentation I could find. I sent my A board in to be repaired and it was returned with a note that it passed all tests and to check other boards. I'm leaning now towards the P board.

All standby power readings are good on my TV and the A board does send a 3.2V "panel_main_on" signal back to the P board, but the tv eventually shuts down and I still get the 12 blink code.

Any suggestions before I search for a P board?

[EIEIO]

Re: Panasonic Plasma TV LED blinking 12 times

Well, I didn't get the same results as PaulF. My replacement P board arrived today and after installing it, I have 10 blinks rather than 12. Following that flow chart, I come to the end and it instructs to replace A board.

Just to confirm, that was my first diagnosis and had sent my A board to Moduslink for repair. They found no problem with it and said it ran for several hours in their test set. They want me to send both my original P and A boards together for testing side by side. It's about $160 each to repair. If both are bad, $320 almost buys me a new set these days.

Any thoughts or suggestions?

[tw2005]

Re: Panasonic Plasma TV LED blinking 12 times

Well, I didn't get the same results as PaulF. My replacement P board arrived today and after installing it, I have 10 blinks rather than 12. Following that flow chart, I come to the end and it instructs to replace A board.

Just to confirm, that was my first diagnosis and had sent my A board to Moduslink for repair. They found no problem with it and said it ran for several hours in their test set. They want me to send both my original P and A boards together for testing side by side. It's about $160 each to repair. If both are bad, $320 almost buys me a new set these days.

Any thoughts or suggestions?

I'm thinking both PSU could be faulty especially since they tested the A and they say it passed.

[EIEIO]

Re: Panasonic Plasma TV LED blinking 12 times

That's kind of what I was thinking. The P board I bought was from a different outfit and came with a 6 month warranty. I guess I'll either send it back for exchange or take the Moduslink (who has been very good to work with) route.

[EIEIO]

Re: Panasonic Plasma TV LED blinking 12 times

FYI, a replacement P board was sent to me and my TV is now working again. Total cost of repair was $86 for the P board and a $50 testing charge on the A board that was originally thought to be the problem.

Thanks Badcaps forum!!