Panasonic TX-P50VT50E completely dead!

[Moreno83]

Hey guys!

Got this beast right here real cheap ( 130£ ) that wont turn on.

Symptoms :

Owner got home after long weekend away from home and tv didnt work.
Powersurge protector had green led......

-Wont turn on at all
-No led is blinking
-No fans are spinning
-No relay clicks
-No voltages on connector P6
-No voltages on Vsus/Zsus


Both fuses on PS are ok and voltages are running over it.
Whole tv is PERFECT , not even a scratch.
Im suspecting the power supply but have not looked in the service manual yet.

Going to download the SM and check the voltages but if anyone has any suggestions....let me know!

[Moreno83]

Re: Panasonic TX-P50VT50E completely dead!

Forgot the mainboard.

[tom66]

Re: Panasonic TX-P50VT50E completely dead!

Check for 5V standby from PSU.

If it's present, then the A board is most likely the fault.
If not, then it's probably the power board -- good chance you can fix it too.

If the 5V is missing, then pull the A board to P board power connectors and re-check, to eliminate a possible shorted A board. If 5V comes back after the connectors pulled the A board may be bad.

Also check the main on/off switch - it's usually just a signal to the PSU - it could go bad, which will cause the PSU to act dead.

[Moreno83]

Re: Panasonic TX-P50VT50E completely dead!

Thx for the reply!


Measured the powerswitch and measuring OL when off and 7.0 Ohms when i hold the PS. ( Probably that much because its on a print with other switches )
Random measurements on power supply with mainboard disconnected :

-No voltages on P6
-30V on capacitor C223 ( next to Vsus 100f)

[tw2005]

Re: Panasonic TX-P50VT50E completely dead!

Thx for the reply!


Measured the powerswitch and measuring OL when off and 7.0 Ohms when i hold the PS. ( Probably that much because its on a print with other switches )
Random measurements on power supply with mainboard disconnected :

-No voltages on P6
-30V on capacitor C223 ( next to Vsus 100f)

just in case you did not get what Tom was meaning. Have you got 5v standby voltage

https://www.badcaps.net/forum/showth...ht=tx-p50xt50e

[Moreno83]

Re: Panasonic TX-P50VT50E completely dead!

Yes i know that i need to search for the 5V standby. Never worked on a tv like this before but I'm not measuring 5V on connector P6 pin 5. ( according to SM ).

The power supply number = NOAE6KL00010

[Moreno83]

Re: Panasonic TX-P50VT50E completely dead!

I could check for that IC? I have a 2012 power supply somewhere! It might have that ic? Will check that tomorrow....going to bed! But damn , what a nice tv!!

[tom66]

Re: Panasonic TX-P50VT50E completely dead!

Call me jealous. Because I am.

VT50 can hold a torch to the legendary Kuro. Can't quite beat it on black level unlike VT60 but it's a friggin nice TV.

[Moreno83]

Re: Panasonic TX-P50VT50E completely dead!

I don't have the "U203" ic with the name "TCZAA6755U".
In another thread i found out that its a 8 legged IC with 1 pin missing?

If so , Mine is I401 and the name is "34A65 PMWB"

[Moreno83]

Re: Panasonic TX-P50VT50E completely dead!

Ps , the production date is august 2013 , it has a newer power supply with a different ic. Same symptoms though.....
I must have warranty on this tv? Don't have the receipt. :o

Anyone any suggestions what it can be?

[tom66]

Re: Panasonic TX-P50VT50E completely dead!

Slow down. Did you check and see if you had 5V yet? The whole power supply is different so of course the IC ref des will be different too. You need to trace where the 5V should come from; If necessary pull the board and trace the circuit back. Most likely it goes to one of the small transformers with a diode and capacitor. Check the diode for short, check the IC, check its input fuse, Vcc capacitor, high voltage supply (~320V) etc.

[Moreno83]

Re: Panasonic TX-P50VT50E completely dead!

Haha sorry , wanna fix this amazing tv! Will try to slow down!

Well , i don't have STBY5V on pin 5 from connector P6. According to the service manual i must measure 5v there. There are absolutely no voltages present on P6 so thats bad.
Reading through the threads about the U203 ic the symptoms are exactly the same but mine is a different ic from a later ps.

I will try and trace back the 5v voltage and see if i can find something , it can be a bad cap right?
The power button line runs though the bottom boards to the PS and not mainboard , not seen that before.....

Will try and search for any faults , if you have any tips please tell me

[tom66]

Re: Panasonic TX-P50VT50E completely dead!

Did you isolate the main board first? to rule out a shorted main board?

[Moreno83]

Re: Panasonic TX-P50VT50E completely dead!

Yes. Disconnected P6 connector but voltages stay the same.

[tom66]

Re: Panasonic TX-P50VT50E completely dead!

OK - get a CLEAR and DETAILED picture of the top (component side) and bottom (green/foil side) of the power board.

[Moreno83]

Re: Panasonic TX-P50VT50E completely dead!

Here you go!

[tom66]

Re: Panasonic TX-P50VT50E completely dead!

A whole picture of the top and bottom would be useful

[Moreno83]

Re: Panasonic TX-P50VT50E completely dead!

Sorry , thought detailed picture. Hope this is ok.

[tom66]

Re: Panasonic TX-P50VT50E completely dead!

Both types are useful. It's just necessary to get the bigger picture and understand the layout.

I can't see the trace clearly enough so you will have to trace the 5V back and point out where it goes.

[Moreno83]

Re: Panasonic TX-P50VT50E completely dead!

I tried to take a better picture from the trace.
Pin5 from P6 ( STBY5V ) trace goes to "JA17" and from there to "R489" to pin 6 from "I552" , this is the trace looking on the back of the power supply.

Service manual says 230v goes into P9 --> rectifier --> P51/P52 --> Standby converter wich outputs 5v standby.

As you can see I'm not good in reading schematics but I'm willing to learn! So forgive my ignorance.