Panasonic TX-P50S20E Y-SUS repair

[PowerAmpFreak]

Hi all,
I've done a repair of a blown Y-SUS, see attachment.
I've changed a lot of blown power components, changed their gate-resistors, driver transistors and driver chips.
When starting up set I get a 7-blink error code.
Is there anything else that use to blow?
Can't find any SMD fuses or such either.
Thanks in advance!

[tw2005]

Re: Panasonic TX-P50S20E Y-SUS repair

Best advice i can give you would be to have a read through my TNPA5081 repair as yours will be a 5105 and it's pretty much identical cct except yours is cut down in number of transistors.

It would also be handy to know what was originally shorted and what exactly has been replaced.

also was the test with buffers or the SC50 buffer board bypass ?

[PowerAmpFreak]

Re: Panasonic TX-P50S20E Y-SUS repair

Thanks, but it went well. I found a small shorted diode which did the trick.
Set is back to life!

All power components marked with a cross on the picture was replaced, and their gate resistors, driver transistors (Y3) and driver chip M51737FP

Everything was tested with correct buffers.

[tw2005]

Re: Panasonic TX-P50S20E Y-SUS repair

Good to hear. So the small diode, was it D451,RF101L4S 400V 1A ?

It would be nice if you could expand on this repair so to help anyone trying to repair these boards.

I'm certainly interested to compare this to the 5081 board. Most of those shorted IGBTs certainly line up with my board.

I am curious to know though, Q661 was shorted but no mention of replacing Q701,702,818 or IC773. Were all those ok?

What was the SOS blinks for the TV with the failed SC board?

So is the entire parts list this?

Q661 RJP63F3A
R665 33 ohm
Q401 DG502LW
R401 7.5ohm
Q402 DG502LW
R402 7.5ohm
Q501 CPH5524
Q421 RJP43F4A
R421 7.5ohm
Q422 RJP43F4A
R422 7.5ohm
Q521 CPH5524
Q451 45G128
R451 5.6ohm
Q551 CPH5524
D482 RFUS20T3S
IC521 M81737FP

[PowerAmpFreak]

Re: Panasonic TX-P50S20E Y-SUS repair

The small diode you mention 400V 1A is correct. Replaced it with a US1J though (600V 1A)
Unfortunately I don't have the TV still here, but basically your list is correct.
Each gate-driver uses an external 5-pin SMD dual transistor marked "Y3", those connected to a blown IGBT or FET were replaced just in case.
One of the M51737FP were actually shorted, but replaced both just in case.
It was kind of a straight work, but be very careful checking the gate resistors and drivers. When have replaced everything blown, please go through the board once again and checking gate resistors and other signs of damage in the gate circuits.
A failed gate resistor could make the board blown once again.

First, before repair of sustain board, set did 10 blinks, (shorted sustain)
After mostly repaired sustain, (the 400V 1A diode still shorted) set did 7 blinks.
After this no blinks and joy

[tw2005]

Re: Panasonic TX-P50S20E Y-SUS repair

Thanks for the feedback. That sounds a very straight forward repair that anyone could successfully complete. I notice one of the kits pretty much has the IGBTs, IC521 fet driver, 2 of the pnp/npn SMD transistors, 1 of those SMD dioes you mentioned..

Interesting to see this board has a very similar failure and design to the TNPA5081 yet those other parts I mentioned survive.

I was looking for a common failure point thinking there was a weak link, maybe a single component which could be upgraded. I was thinking the HA schmitt inverter IC because 3 from 3 boards I did they were all shorted.

Your board suggests otherwise.