Panasonic TC-P65VT50 7 blinks

[djw43]

Hi
I have a thread for a TC-P50GT25 but thought it is better to start a new thread.
https://www.badcaps.net/forum/showthread.php?t=45071

I just received this big boy and have removed the SC card, SC2 is shorted, I have checked the Q's (transistors) and have not found any shorts between legs. There is one area of the board that has some short tones however.
see pics
R588 one side shorted to ground (233)
C551 one side short to ground
C453 one side short to ground
Q453 E short to ground 45F132 012 1229 (also q452, q451,)
q421, q422, q423 DG301227C7u also have E short to ground
diodes d462, d463, ( RFUH20 NS3S) and d421, d422 (DAF30A 141C5d) 2 legs each short to ground
IC524 pin #2, #5, #6 short to ground part 4840 NA5 JRC

Also, resistor R453 (5R6) is shorted end to end
And D583, which looks like an LED, has open circuit both directions with diode test.

I would like to try and repair this board, it is also available from shopjimmy
there is another thread for a similar problem with a TC-P55VT50, fixed by replacing the SC
https://www.badcaps.net/forum/showth...ght=tc-p55vt50
Anyone feel like it could be repaired DIY? tw?

[tw2005]

Re: Panasonic TC-P65VT50 7 blinks

It's repairable, but might be as cheap to get a board too. that way you can have fun trying to repair and have a working TV too.

[djw43]

Re: Panasonic TC-P65VT50 7 blinks

It's repairable, but might be as cheap to get a board too. that way you can have fun trying to repair and have a working TV too.

that's a great idea, I am going to order an SC on ebay, and then try to repair the faulty one.
Do you think I am on the right track with those shorted components?
Those are really the only shorts, other than the legs of the diodes that also give short tones. And SC2 is shorted.

Would it make sense to lift those components off the board and see if SC2 is no longer shorted?
thanks again tw

[CapLeaker]

Re: Panasonic TC-P65VT50 7 blinks

It is good practice to double check your findings out of the circuit. It is extremely rare for resistors to short. Usually the go higher in resistance, or open circuit. So the first 3 items on your list may be normal as one side actually is ground. So take all the offender you think out of circuit and measure again. Things could read a short in circuit, while not out of circuit. Have fun!

[djw43]

Re: Panasonic TC-P65VT50 7 blinks

It is good practice to double check your findings out of the circuit. It is extremely rare for resistors to short. Usually the go higher in resistance, or open circuit. So the first 3 items on your list may be normal as one side actually is ground. So take all the offender you think out of circuit and measure again. Things could read a short in circuit, while not out of circuit. Have fun!

Thanks very much for the input, I will pull those components off the board.
I just double checked IC524 and pin 2,5 and 6 are shorted to each other and to floating ground on the board.
Should those Q transistors have the "E" leg short to ground?
Thanks again

[Shinju]

Re: Panasonic TC-P65VT50 7 blinks

If this was mine I would send the old board to moduslink and have them repair it vs buying a shot in the dark used board that might fail.

Mostly due to these boards being a pain to get the SMD parts off with out ruining the copper pads.

Test your buffers too.

[tom66]

Re: Panasonic TC-P65VT50 7 blinks

You can see all those parts are connected to the copper ground plane. A short is normal. BTW, it is better to test across parts rather than from pin to ground - that way you can eliminate the need to find which pin is grounded (it doesn't matter)

Have you tried isolating buffers and jumpering SC50?

[djw43]

Re: Panasonic TC-P65VT50 7 blinks

If this was mine I would send the old board to moduslink and have them repair it vs buying a shot in the dark used board that might fail.

Mostly due to these boards being a pain to get the SMD parts off with out ruining the copper pads.

Test your buffers too.

Thanks Shinju, I appreciate all suggestions!
I actually sent a TNPA5081 (GT25) to modulus this week because that part seems to be so difficult to find. The cards for the bigger 2012 VT50 seems to be more available, $25 to $75 so I thought it would be an advantage to have a spare card, and also if it did work, to have a reference to try and repair the original SC from the TV myself. I did invest in a small rework station and preheater to do the best I can to avoid damaging the tracks or pads.
Thanks again, I can use all the advise I can get, and I WELCOME it!

You can see all those parts are connected to the copper ground plane. A short is normal. BTW, it is better to test across parts rather than from pin to ground - that way you can eliminate the need to find which pin is grounded (it doesn't matter)

Have you tried isolating buffers and jumpering SC50?

Hi tom,
Thank you for lending a hand!
I do see now that you pointed it out, the solid ground plane that covers so much of the board. But for IC 524 it didn't seem normal for 3 pins to be connected to ground.
I have quickly done some readings on some of the parts I listed above, but I still have many more to measure. all measured in circuit
q421, q422, q423 all EG 99k GC 179k EC47k
q451 EG 99k GC 290k EC 580k
q452 99k 290k 112k
q453 99k 290k 112k

d462 600k/108k and .36/.36 diode test
d463 28k/108k and .36/.36 diode test
d421 46k/46k .26/.26
d422 46k/46k .26/.26


thanks very much guys

[tw2005]

Re: Panasonic TC-P65VT50 7 blinks

Thanks Shinju, I appreciate all suggestions!
I actually sent a TNPA5081 (GT25) to modulus this week because that part seems to be so difficult to find. The cards for the bigger 2012 VT50 seems to be more available, $25 to $75 so I thought it would be an advantage to have a spare card, and also if it did work, to have a reference to try and repair the original SC from the TV myself. I did invest in a small rework station and preheater to do the best I can to avoid damaging the tracks or pads.
Thanks again, I can use all the advise I can get, and I WELCOME it!



Hi tom,
Thank you for lending a hand!
I do see now that you pointed it out, the solid ground plane that covers so much of the board. But for IC 524 it didn't seem normal for 3 pins to be connected to ground.
I have quickly done some readings on some of the parts I listed above, but I still have many more to measure. all measured in circuit
q421, q422, q423 all EG 99k GC 179k EC47k
q451 EG 99k GC 290k EC 580k
q452 99k 290k 112k
q453 99k 290k 112k

d462 600k/108k and .36/.36 diode test
d463 28k/108k and .36/.36 diode test
d421 46k/46k .26/.26
d422 46k/46k .26/.26


thanks very much guys

nothing's leaping out at me short wise. across the sc2 pins what resistance? are you getting

[djw43]

Re: Panasonic TC-P65VT50 7 blinks

nothing's leaping out at me short wise. across the sc2 pins what resistance? are you getting

short .000 SC2

not seeing any shorts on any other qxxx between legs or to the C

gotta head out for work
thanks all!

[tw2005]

Re: Panasonic TC-P65VT50 7 blinks

short .000 SC2

not seeing any shorts on any other qxxx between legs or to the C

gotta head out for work
thanks all!

SC2 was measured isolated from the P board? If SC2 is short, ther's IGBTs shorted on the SC, there somewhere or have a go at the SC50 jumper, disconnect the buffers from the SC and remove the Vfg bolts(the ones that earth these to the SC)

[djw43]

Re: Panasonic TC-P65VT50 7 blinks

SC2 was measured isolated from the P board? If SC2 is short, ther's IGBTs shorted on the SC, there somewhere or have a go at the SC50 jumper, disconnect the buffers from the SC and remove the Vfg bolts(the ones that earth these to the SC)

i have the SC board completely removed from the TV.
i just checked the resistance at SC2 again with SC50 jumped and not still dead short at SC2
gotta head out though , i will test the individual components again later
thanks tw

[tw2005]

Re: Panasonic TC-P65VT50 7 blinks

i have the SC board completely removed from the TV.
i just checked the resistance at SC2 again with SC50 jumped and not still dead short at SC2
gotta head out though , i will test the individual components again later
thanks tw

sorry, should expanded. the sc is installaed and powered up with the buffers isolated and their gnd bolts removed, this wil prove id SC is working or not. if ok tv will turn on with no errors but if sc2 is shorted, no point.

[tom66]

Re: Panasonic TC-P65VT50 7 blinks

i have the SC board completely removed from the TV.
i just checked the resistance at SC2 again with SC50 jumped and not still dead short at SC2
gotta head out though , i will test the individual components again later
thanks tw

Make sure to hold the probes for some time when testing w/ P board, as the caps can take some time to charge. Also check Vsus on P board (~215V) when powering up. If low, could be issue with SC/SS shorted or P board bad.

Not sure how these newer Pannys work, could a shorted Vsus trip SOS7 because Vscn/Vad did not rise when expected? (I would have thought it would trip out a different error first...)

[tw2005]

Re: Panasonic TC-P65VT50 7 blinks

Make sure to hold the probes for some time when testing w/ P board, as the caps can take some time to charge. Also check Vsus on P board (~215V) when powering up. If low, could be issue with SC/SS shorted or P board bad.

Not sure how these newer Pannys work, could a shorted Vsus trip SOS7 because Vscn/Vad did not rise when expected? (I would have thought it would trip out a different error first...)

ST50 guide , should be of some help

[tom66]

Re: Panasonic TC-P65VT50 7 blinks

Yea, so 7 blinks can be "Missing or shorted Vsus" according to that doc.

Seems to indicate that P board doesn't trigger it, rather that SC triggers it because the sub voltages don't come up (7 blinks usually Vscn/-Vad check)

Some older panels will do 6 blinks as ER mid has "priority" over 7 blinks, but I guess it depends entirely on the model as to exactly what each does...

[djw43]

Re: Panasonic TC-P65VT50 7 blinks

ST50 guide , should be of some help

cool, i hadn't seen that second doc, but that is the guide I followed, 7 blinks, disconnect P11, still had 7 blinks, disconnected SC20 went to 8 blinks, then found a short on one pin on each SU41 and SD42 and then did not have a short when disconnected those clips from SC. I then isolated SU/SD and the TV still clicked off indicating bad SC. And the SC2 shows a dead short.
that's when I started checking the components on the SC out of the TV.

[djw43]

Re: Panasonic TC-P65VT50 7 blinks

MAJOR EDIT

And I apologize for anybody's wasted time!

I just double checked my SC50 jumper, and I was not getting continuity.

So i stuck a different jack in there with SU/SD isolated and powered up, 3 relay clicks then power button, which caused some buzzing sounds from near the SC and also the SS board.
The fans spin, and the LEDs are on both SC and SS.
The diagnostics point to SU/SD, i did the probe test on them and did not find any shorts running the probe across the pins on each of the 10 panel connectors.
But unless anyone has any other thoughts, I am going to order an SU and SD

thanks and sorry for the misdirection

[tom66]

Re: Panasonic TC-P65VT50 7 blinks

Just to be sure, no cracks at all on the plasma panel? Even ones right on the edge?

[djw43]

Re: Panasonic TC-P65VT50 7 blinks

Just to be sure, no cracks at all on the plasma panel? Even ones right on the edge?

I will check closely as soon as I get home
thank you tom