Panasonic TC-P50G15

[cliff_hootarski]

I bought this TV from a person on Craig's List. They said a technician came in and diagnosed a bad power supply (too much money to fix). Original symptom no picture, and front led blinking three times.

Well of course I believed them and bought a used power supply on Ebay. Installed the power supply and when I plug the TV in, I hear a clicking of a relay, the front panel led comes on solid red, and then about 13 sec. later the relay clicks again and the front led starts blinking. It blinks 1 time at an interval of 4 seconds and continues blinking at that interval until power is removed from the TV. I re-installed the original board and still got the 1 blinking light code.

The service manual blinking light code indicates a failure of the "A" board (main board) but at an interval of 3 seconds.

I've fixed a few LCD tv's and this is my first foray into Plasma TV's.

I've got a distant background in electronics (Air Force enlisted 30650 Crypto).

[PlainBill]

Re: Panasonic TC-P50G15

I bought this TV from a person on Craig's List. They said a technician came in and diagnosed a bad power supply (too much money to fix). Original symptom no picture, and front led blinking three times.

Well of course I believed them and bought a used power supply on Ebay. Installed the power supply and when I plug the TV in, I hear a clicking of a relay, the front panel led comes on solid red, and then about 13 sec. later the relay clicks again and the front led starts blinking. It blinks 1 time at an interval of 4 seconds and continues blinking at that interval until power is removed from the TV. I re-installed the original board and still got the 1 blinking light code.

The service manual blinking light code indicates a failure of the "A" board (main board) but at an interval of 3 seconds.

I've fixed a few LCD tv's and this is my first foray into Plasma TV's.

I've got a distant background in electronics (Air Force enlisted 30650 Crypto).

Tip 1. Sellers on Craigslist often lie. If they want to meet you in a parking lot, the chances they are lying increase. If you don't have a chance to verify the error, don't spend the money.

I checked my usual sources and was unable to find a service manual for this set. If the manual lists the power supply outputs, verify they are correct (it wouldn't be the first time someone sold a defective power supply on eBay).

Also, try disconnecting the power cables from the Y and X sustains and see if that changes anything.

PlainBill

[cliff_hootarski]

Re: Panasonic TC-P50G15

Thanks for the advice about CL and Ebay. I fully understand the pitfalls from buying unknown items from unknown persons.

Attached is the pwr. supply schematics. I have the entire schematics if any others are needed.

I'll check to see what outputs I get on the pwr. supply.

My original post should have stated the TV has no video or sound.

[weirdlookinguy]

Re: Panasonic TC-P50G15

Would you mind posting the full service manual? Just to add to my collection.

[cliff_hootarski]

Re: Panasonic TC-P50G15

It seems the entire manual is too big to upload to this site.

[ibgm]

Re: Panasonic TC-P50G15

I'm working on this TV and don't ask, but I shorted out D503. I now know it is a double diode, a zener in one direction and a regular diode in the other. (wish I knew that before!) But anyway, I need to replace it. Would you be able to tell me from your manual what part number it is? The number I read on the diode is T3D9 1 I can't find a cross for it anywhere. Thanks in advance!

[tw2005]

Re: Panasonic TC-P50G15

I'm working on this TV and don't ask, but I shorted out D503. I now know it is a double diode, a zener in one direction and a regular diode in the other. (wish I knew that before!) But anyway, I need to replace it. Would you be able to tell me from your manual what part number it is? The number I read on the diode is T3D9 1 I can't find a cross for it anywhere. Thanks in advance!

I need more info like what board?

If you're rebuilding a SC, maybe you'd like to go through this post and share any info you may have. TC-50PS14

EDIT: Ok, I think I know which board. The P-board VXST3D82BL3 is the full number, location D503. I think I've looked for something like this before, took forever to find for a PC PSU.

[tw2005]

Re: Panasonic TC-P50G15

Ok, I got it. TRANKILLER ,Power Clamper, ST03D-82, by Shindengen

•Power Zener Diodes with FRD

On another Panasonic PSU, I have 120V diode, in cct it bells short, 1ohm across but sits across a transformer winding. No idea how they should test out.

[ibgm]

Re: Panasonic TC-P50G15

Thank you so much for the information. I work at a company that manufactures diodes, I'll be able to make up one of these. (I'll take 2 seperate diodes and tie them together in the proper configuration) Now that I know the specs, I can fix my mistake. Having this forum has been very helpful. The schematic that Cliff posted and the datasheet from tw2005 have bailed me out big time. Thanks Guys!

[ibgm]

Re: Panasonic TC-P50G15

I was just reviewing the drawing that was attached to an earlier post on this thread, specifically, page 002. The schematic shows the D503 as being a common anode configuration, the ST03D-82 is a common cathode! I'm glad I didn't install it yet. Now I'm back to the drawing board, maybe I can get some more info from Shindengen, that's where the data sheet came from. In the mean time, if anyone has an exact part number for the D503, I would be much obliged!
This diode is on the main power supply board ( pic # 2 on first of this thread)

[ibgm]

Re: Panasonic TC-P50G15

Using a Tektronix Curve Tracer in the AC mode, I noticed that in either configuration, the zener continues to fuction as a zener and the rectifier acts as a rectifier. I'm a little confused, maybe it doesn't matter?
tw2005, did you get the p/n from the actual shop manual? Cliff, does it say in your shop manual the actual p/n?

[tw2005]

Re: Panasonic TC-P50G15

Using a Tektronix Curve Tracer in the AC mode, I noticed that in either configuration, the zener continues to fuction as a zener and the rectifier acts as a rectifier. I'm a little confused, maybe it doesn't matter?
tw2005, did you get the p/n from the actual shop manual? Cliff, does it say in your shop manual the actual p/n?

I've given you both the panasonic listed part number and the OEM part number, the manual will only give Panasonics reference and unless it's a Panasonic item the part number is rarely shown as the true number.

You can seean abbreviated part number within the Panasonic number.

SEach ST3D82 and you'll get a hit.

[ibgm]

Re: Panasonic TC-P50G15

Thanks tw2005. I just got thrown off by the contradiction in the schematic when comparing it to the datasheet. I'm going to give it a try. I appreciate you help with this. I would love to get this set going!

[ibgm]

Re: Panasonic TC-P50G15

Update:
I replaced the diode with the one I made up, now I'm back to my original problem, solid red light, lots of clicking relays, the boards on either side of the p/s have solid green led's lit up, but no picture or sound.

[tw2005]

Re: Panasonic TC-P50G15

So the panel is energised? Do the relays click like it's resetting and restarting all the time?

Sounds like it could be the A-board. You could try disconnecting all the ribbons from the A-board, power from the SC, SS and any power to the C buffers and powerup and see what it does?

I have done this on a 2010 HD model to prove the A board was ok and the TV just turned on normally minus a a picture.

[ibgm]

Re: Panasonic TC-P50G15

Yeah, the panel is energised, it glows faintly. ( I didn't even realize that until I turned the lights out in the room)
If I unhook the ribbon cables (the flat ones) from the A board and remove the power cables from the sc and ss boards and try to turn it on, what exactly should I expect? There is a small connector on the power supply board, is that the supply for the c board?
I did try some of this last night, but when I powered up the set, I got no lights. Pretty sure this is pointing to the A board which is a shame, they want crazy money for it. Wish I could figure out what part goes bad on the A board.
With the panel being energised, does that point to the A board? The panel glows for a few minutes, then shuts down.

[tw2005]

Re: Panasonic TC-P50G15

Interesting, panel shutting down could simply be panel save due to no signal? Shutsdown all power off or glow disappears?

Yes the small cable could be to the C buffers. I'd disconect that too, I trust you have the manual. You should be able to work out where that lead goes.

But if your not getting any SOS and panel primed then probably no point doing this now.

So no SOS blinks, panel primed?

Try this if it's powered up and primed panel, it's a longshot. Select TV, have no antenna connected, on the rear there should be video out or AV out, connect that to another TV and see if you get a display possibly the NO SIGNAL banner.

If so the A board has booted up ok.

Can you clarify lots of relay clicks? How many? or is it continuous clicking ??

I have produced a situation of everything on but just a greyed primed screen and it was a faulty octal buffer IC that takes the A board signal at SC20. I guess it could be at either end and on mine theres 2 on the SC and also on the A board as well

[ibgm]

Re: Panasonic TC-P50G15

Sorry for the delay. I'll start from the beginning, I found this TV at the dump, so I don't know the back story...
When I first plug the set in, I get a single relay click, then after a few seconds, I get a second relay click. Then, I hit the Power switch, I hear the relay again, the backlight is activited (dim, but definitly on) and when I look in the back, the boards on either side of the p/s have green LED's on. The Red power light stays on steady, no flashing.There are no Video outputs on this model, so I can't try another monitor.
Here's where it gets a little weird, when I shut the set off using the Power button, the Red light goes off but the backlight stays active for about 30 seconds, it does eventually go off. I also noticed that when I hit the Power button directly after shutting the unit down, it won't come back on right away, I have to wait about 30 seconds. And then when it does come back on, If I hit the power button, it doesn't seem to do anything, the Red light stays on, eventually it will shut off.
I don't have a shop manual for this, does this sound like it could be coming from the p/s? I wish I had a manual that would tell me what measurements I should read on the testpoints on the p/s.
Thanks for listening and I appreciate any and all feedback!

[cliff_hootarski]

Re: Panasonic TC-P50G15

Started this post over 3 years ago. Finally got around to try to fix this thing.
Finally found a mainboard on *Bay, and got this thing fixed!
It's been on the back burner long enough.

[matyka]

Re: Panasonic TC-P50G15

Hello, on my p board D-503 diode is shorted anybody know from where to buy in uk a replacement for part number: VXST3D82BL3 ,thx