Panasonic TC-P50VT20

[ljintexas]

Re: Panasonic TC-P50VT20

A6 disconnected readings of pins on A board
pin 1 = 1.1Mohm, pin 2 = 4.7Mohm, pin 3 = .6 ohm, pin 4 = .6 ohm, pin 5 = .6 ohm, pin 6 = 12.8Kohm, pin 7 = 12.8 Kohm, pin 8 = 12.7Kohm, pin 9 = .6ohm, pin 10 = .6 ohm

with sc and ss disconnected, faults on 7 blink SOS.

SC and SS connected sc=2.2 volts, ss=2.2 volts
only ss connected sc=208volts ss=169 volts
only sc connected sc = 2.2 volts ss = 2.2 volts
no sc or ss connected sc = 208 volts ss = 208 volts

With both connected and A6 connected again back to 10 blinks.

[tw2005]

Re: Panasonic TC-P50VT20

something is wrong, can't be possible to have 208 on sc side and 169 on SS side, it's the same volatage produced for both in one cct so both have to equal the same.

can you locate TP82 on the Sc, near Sc20 connector and check resistance - gnd pad on sc board. that's the 15V in for that Sc.

[ljintexas]

Re: Panasonic TC-P50VT20

My bad..We have 208 on sc side and 198 on ss side with only ss connected. TP82 reads 2.13Kohms to ground pad on board.

[tom66]

Re: Panasonic TC-P50VT20

Are you sure you have different voltages? The same PSU output should be used for both. They should read roughly the same.

[ljintexas]

Re: Panasonic TC-P50VT20

If I disconnect ss board AND sc board, they will be the same. with only ss connected, ss reads 198 and sc reads 208.

[ljintexas]

Re: Panasonic TC-P50VT20

Once 15 sec has expired and shutdown occurs..reading on ss goes to 204 then starts bleeding down.

[tw2005]

Re: Panasonic TC-P50VT20

well, I don't know if I'm barking up the wrong tree but it's not making much sense,.

Losing vsus with the Sc says to me bad SC, also no 10 blink but 7, if the F15v and subs were being shorted I'd expect vsus not to get up and still 10 blink.

I'm winging this next suggestion.

Disconnect
Sc2, Sc20,ss11, p35, at the d board, disconnect any ribbon that feeds any c board upper or lower, leave connected to the A.

power it up and see if it blinks or stays on. don't reconnect anything. I'll see if I can dig up the aussie A-board and measure those A6 points, not sure if they match up or not with my version.

[tw2005]

Re: Panasonic TC-P50VT20

oh, and only run for 30sec or less or the TV will shutdown with an error, maybe 4 blink

[ljintexas]

Re: Panasonic TC-P50VT20

Will try it this afternoon. Thanks! If we suspect sc, should we test su and sd to make sure they did not whack sc?

[ljintexas]

Re: Panasonic TC-P50VT20

I have access to an sc board within a couple days.

[tw2005]

Re: Panasonic TC-P50VT20

good idea to check buffers, yes.

still not happy to commit to what's going on yet. looking for that smoking gun

[ljintexas]

Re: Panasonic TC-P50VT20

Good news is we have time..what is good test procedure for su and sd?

I appreciate your time and effort! If you ever need anything from this side of the world, just let me know.

[tw2005]

Re: Panasonic TC-P50VT20

what I need is some clear cut evidence. LOL

unfortunately I'm trying to upgrade my pc so I can't access my files. not going well.

the g20,g25 guide has a good resistance check, I'm not good enough to remember the exact pins and readings , have posted this a few times now.

[tw2005]

Re: Panasonic TC-P50VT20

https://www.badcaps.net/forum/attach...5&d=1430296122

sd/su resistance tests are in that, I think VFO, Vscn, vf5v, could have those muddled but you'll see when you read it

[ljintexas]

Re: Panasonic TC-P50VT20

I grabbed the G20/G25 tech manual..good info in there.. I will test the buffers.

Thanks

[ljintexas]

Re: Panasonic TC-P50VT20

Disconnect
Sc2, Sc20,ss11, p35, at the d board, disconnect any ribbon that feeds any c board upper or lower, leave connected to the A.

power it up and see if it blinks or stays on. don't reconnect anything.

LED Stays on solid...no blinky

Everything still disconnected. AFO

[tw2005]

Re: Panasonic TC-P50VT20

Disconnect
Sc2, Sc20,ss11, p35, at the d board, disconnect any ribbon that feeds any c board upper or lower, leave connected to the A.

power it up and see if it blinks or stays on. don't reconnect anything.

LED Stays on solid...no blinky

Everything still disconnected. AFO

ok, well my washing machine just died, looks like i'll be busy fixing my problems but that suggests it was on, I would have then check vsus again to confirm on and voltages feeding the a board especially 15v.

Seems like SC but we just have not found a part shorted, feel free to keep looking I'd check all the IGBT transistors on the heatsinks.

If it is on, that means 10 blink is not P, A or D but 1 of the other boards.

That's about the best i can do without spending ages looking at the diagrams, i guess potential short or c boards may cause it but the loss of vsus with SC connected and restored with it removed strongly suggests that is the most likely item.

Good luck, I'm heading out tonight and I'm a little stressed hope you understand,

[ljintexas]

Re: Panasonic TC-P50VT20

Thanks for you r help. Just fixed a whirlpool Vertical Modular Washer..it needed a shift actuator and a mixing valve..I am going to remove and analyze SC..My money is on it.

[ljintexas]

Re: Panasonic TC-P50VT20

If I can assist with washer..let em know fixed a ton of them through the years.

[ljintexas]

Re: Panasonic TC-P50VT20

SU and SD read OL on all resistance tests. Wierd.