50" Panasonic Plasma dead.

[titodj]

I got a 50" Panasonic Plasma model th-50px75u that wont power up.
When I plug it, I can hear a click.
But after that if I press the power button, I just get a static red led, no blinking or nothing.

Any way, I got a troubleshooting diagram from scribd, and followed the steps for No power/ Dead Unit.

In pin 20 of D5 I got 3.0v
and in pin 11 of P25 I got 3.2v

So according to that diagram there is something wrong with the power supply. (power supply ETXMM655MEH )
I did a visual inspection, and I cant see anything obvious, and measured continuity in all the fuses I saw.
But thats about it, I dont know what else to look for.
Im attaching some pictures of the power supply.

Thank you in advance for your help, and kind attention.

[titodj]

Re: 50" Panasonic Plasma dead.

Quick update.

Looking in youtube how to check diodes, I found that two of them apear to be opened, im posting the pictures to see if this can help.

Thanks again.

[retiredcaps]

Re: 50" Panasonic Plasma dead.

Looking in youtube how to check diodes, I found that two of them apear to be opened,

1) Are you using the diode test function on your multimter?

2) If yes, post the actual readings. You should have 2 readings per diode.

[titodj]

Re: 50" Panasonic Plasma dead.

Yes I'm using my multimeter.

The first one (the one next to what looks like a coil)

.168 and .520

The second one (next to the yellow thing)

.001 (after a while of jumping all over it settel's there)
.003

Thanks.

[tom66]

Re: 50" Panasonic Plasma dead.

Second one seems bad.

[retiredcaps]

Re: 50" Panasonic Plasma dead.

The second one (next to the yellow thing)

.001 (after a while of jumping all over it settel's there)
.003

The second is shorted (not open). Remove it and retest out of circuit.

[titodj]

Re: 50" Panasonic Plasma dead.

Thank you, I finally got to take the power supply off, and remove the diode.
off circuit reads "OL" on both directions.

So I assume the diode is bad.
Now, I have a few questions, should I look for something else in the power supply?
Is that diode alone likely the cause of the failure?
The diode is the Panasonic ST3D82 Diode Surge Protector

Should I just replace the diode and test? or test something else and then replace??

Also the first diode that I mentioned in this thread, its fine even tough it gives readings in both directions?

The first one (the one next to what looks like a coil)

.168 and .520

Thanks again, for your help.

[tom66]

Re: 50" Panasonic Plasma dead.

That diode is probably good (it is a TVS, so will not conduct normally); is it still reading a short between the terminals on the PCB, where you removed the diode?

[titodj]

Re: 50" Panasonic Plasma dead.

If i use the continuity test between the two empty terminals where the diode was, I get a beep

If I use the diode mode I get 0.00 so I guess "yes"?

I get a shorts between the terminals.

[tom66]

Re: 50" Panasonic Plasma dead.

OK, so there is still a short. Which area are you testing? (I'm not sure which one it is the picture.)

[titodj]

Re: 50" Panasonic Plasma dead.

I took out the diode next to what it looks like a yellow transformer.
And I'm getting a "beep" between the terminals where the diode was.

Thanks.

[tom66]

Re: 50" Panasonic Plasma dead.

That MAY be normal, as the diode is simply there to protect the transformer which will read as short. I think you need to look elsewhere.

[titodj]

Re: 50" Panasonic Plasma dead.

Thanks, I wil replace the diode, and see if that helps.

[cuestaj1707]

Re: 50" Panasonic Plasma dead.

Hi dear titodj,I'm working in the same power supply and i tried some thigs but still no find the solution,replaising this diode fix your problem?,because i have the same in mine,thanks.

[cadiman]

Re: 50" Panasonic Plasma dead.

I have replaced large caps on some of the other types of plasma power supplies.

I would check or replace the large caps in the secondary part of the supply.

[cuestaj1707]

Re: 50" Panasonic Plasma dead.

I have replaced large caps on some of the other types of plasma power supplies.

I would check or replace the large caps in the secondary part of the supply.

I have two sets of large caps one whit 3 caps 900 uf 220 v and others 3 220uf 450 v this last one is the one close to the 110 v main entry which one is the one that you guess is give me a problem,thanks

[titodj]

Re: 50" Panasonic Plasma dead.

Just to update this thread.

After replacing the three big capacitors (450 v 220uf) I was able to hear the relays click, but still no go...

So following the flow charts in this excellent troubleshooting manual, I was able to pinpoint the problem in the GS board, so decided to take out the GS board...

And... BINGO !!!

I found a 5cts coin stuck in the SD card slot !!!

A pair of needle nose pliers and one minute later, the problem was resolved !!

[tom66]

Re: 50" Panasonic Plasma dead.

LOL! Awesome! Interesting that a coin would cause that, but I guess it acts as a nice shorting block!
Oh, and you're 5 cents richer

[spidey12345]

Re: 50" Panasonic Plasma dead.

I have the same issue. My son stuck a washer stuck in the SD card slot, as it looked like the slit on his penny bank. I pulled it out, but now the TV is stuck on channel 3, and it wont change channels or adjust the volume, it pretty much turns on and off to channel 3 and I cant change to HDMI nor any other input.

Any ideas how to address the issue. I've been reading that there is a way to disconnect the SD reader permanently....its a 6 year old 50 inch Panasonic Plasma...

thaks

[tom66]

Re: 50" Panasonic Plasma dead.

I would check the button board connectors are seated correctly and no buttons are stuck.