Panasonic TX-P42GT20B - Stuck Stby

[tw2005]

Re: Panasonic TX-P42GT20B - Stuck Stby

Random thought, Just posted elswhere but I had an A board 10 blinker, shorted 3.3v line, SD card slot damaged and bent pins shorting out. Most likely foreign object inserted (kids?)

[tn245]

Re: Panasonic TX-P42GT20B - Stuck Stby

My 3.3V is ok. I'm missing MIHO 3.3V and in fact LED 8V. But those will only come up when the MPU sends PANEL_MAIN_ON, which it isn't doing.

[benjamin.d.bird]

Re: Panasonic TX-P42GT20B - Stuck Stby

i have looked over the schematics but cant fathom where or on which pins/connectors i should be checking for the voltages.

also got hold of different DMM hopefully this one will be capable lol

[tn245]

Re: Panasonic TX-P42GT20B - Stuck Stby

Maybe try the resistance readings again on Q661 on sc board with the new meter. From the readings you posted before and the sc light not coming on when the ss did I suspect it is shorted.

[benjamin.d.bird]

Re: Panasonic TX-P42GT20B - Stuck Stby

on q661 it beeps on all 3 legs
on sc nothing

[ReeceyBurger123]

Re: Panasonic TX-P42GT20B - Stuck Stby

Q661 is the issue then dragging the whole SC into the dirt.

[benjamin.d.bird]

Re: Panasonic TX-P42GT20B - Stuck Stby

So if I buy a working SC board then all will be working?

[benjamin.d.bird]

Re: Panasonic TX-P42GT20B - Stuck Stby

i dont seem to be getting any V at P2 with sc disconnected,

[tw2005]

Re: Panasonic TX-P42GT20B - Stuck Stby

So if I buy a working SC board then all will be working?

i dont seem to be getting any V at P2 with sc disconnected,

How about p11? And it's going to be around 200V and may only be there momentarily if the TV is shutting down

[benjamin.d.bird]

Re: Panasonic TX-P42GT20B - Stuck Stby

How about p11? And it's going to be around 200V and may only be there momentarily if the TV is shutting down

SC Disconnected
P11 pin 4 = 15.58v
pin 1 = 201v
P2 pin 1 = 207v

SC Connected -
P11 pin 4 = 15.58v
pin 1 = 0v
P2 pin 1 = 0v

[tw2005]

Re: Panasonic TX-P42GT20B - Stuck Stby

SC Disconnected
P11 pin 4 = 15.58v
pin 1 = 201v
P2 pin 1 = 207v

SC Connected -
P11 pin 4 = 15.58v
pin 1 = 0v
P2 pin 1 = 0v

I believe that is a strong indication SC is short. If it shows voltage at the SS when the SC is disconnected and nothing when connected then SC is the issue I feel. Will replacing the SC fix everything, no idea, but that's the evidence you have provided.

[benjamin.d.bird]

Re: Panasonic TX-P42GT20B - Stuck Stby

ok i have one on order "should" be here tomorrow.
First of all am i ok just to put it in, connect it up and hope for he best or did i read some where in your long thread about the buffer board making it go popo again or am i just getting my wires crossed (for want of a better phrase).
Second if all is well do you or Tom want the original board?

[tw2005]

Re: Panasonic TX-P42GT20B - Stuck Stby

ok i have one on order "should" be here tomorrow.
First of all am i ok just to put it in, connect it up and hope for he best or did i read some where in your long thread about the buffer board making it go popo again or am i just getting my wires crossed (for want of a better phrase).
Second if all is well do you or Tom want the original board?

I'm in Oz Tralia mate, I got 6 of them for 50" already , dunno what I'm going to do with them , thanks all the same.

[tn245]

Re: Panasonic TX-P42GT20B - Stuck Stby

Before you put the new board in check it over carefully, do those resistance readings on it especially on Q661. I recently bought a "working" tnpa5081. Found Q661 shorted right away. Then noticed another IGBT was totally exploded. The exploded IGBT was clearly visible on the guys ebay pic too once I knew what to look for so was not difficult to get a refund.

Yes check buffers for shorts. Make sure all is screwed in tightly and properly connected. You can test the SC with SC50 jumper in before making connection between SC and buffers.

[benjamin.d.bird]

Re: Panasonic TX-P42GT20B - Stuck Stby

Well my replacement SC board arrived this morning..............
.......However, the board that i received is a "fully tested" TNPA5081 AW.
I assume that as one is for the 50" and the other for the 42" board needs returning?
good news is that Q661 is ok (wry smile)

[tw2005]

Re: Panasonic TX-P42GT20B - Stuck Stby

Well my replacement SC board arrived this morning..............
.......However, the board that i received is a "fully tested" TNPA5081 AW.
I assume that as one is for the 50" and the other for the 42" board needs returning?
good news is that Q661 is ok (wry smile)

Fair dinkum 100% wrong board.

TXNSC11NEK or TNPA5081AH

Since the same board is used in both the 2D and 3D models you may get away with it for a quick test and confirm that's all you need.

But, i would check the sd and su boards are not shorted or perform the 7 Blink SU/SD board isolation test where you fully install the sc bit don't connect the SD or SU, jumper the small 2 pin connector on the SC at SC50 (lower left )

If the TV now turns on and stays on with the green LED, then that would be good and turn the TV off,

Get the right board or you could try converting which would involve swapping out a bunch of capacitors and coils from your old board to the replacement.

[tw2005]

Re: Panasonic TX-P42GT20B - Stuck Stby

make sure the SD/SU gnd bolts are not bolted to the SC as well if doing that bypass test.

[benjamin.d.bird]

Re: Panasonic TX-P42GT20B - Stuck Stby

ok passed bypass test, how do i make sure sm didnt blow sc board to start with?

[tw2005]

Re: Panasonic TX-P42GT20B - Stuck Stby

ok passed bypass test, how do i make sure sm didnt blow sc board to start with?

well, if you have a meter in diode and continuity beep, place one probe on SD/Su board gnd plates(bolt plates) and slide the other carefully along the contact pins on the output ribbon connectors watching for dead short.

[benjamin.d.bird]

Re: Panasonic TX-P42GT20B - Stuck Stby

Fair dinkum 100% wrong board

you could try converting which would involve swapping out a bunch of capacitors and coils from your old board to the replacement.

any ideas on how many/which ones would need swapping out?
and if its just coils and caps which i am capable of but anything involving micro surgery then i'd be at a loss!