Panasonic TCP50GT20

[tw2005]

Re: Panasonic TCP50GT20

Can somebody do a video of this like tom66 did for buffer boards?

https://www.youtube.com/watch?v=51SZ...DtCVe9&index=6

I'm camera shy , and I don't want to come across as a know all but what are you unsure about. Buffer boards I've always been a little low on confidence with but having a look at the block diagram I've posted above a little you can see what pins the inputs are so not a bad place to start. The other thing is to do tha same between the gound plate and the outputs at the panel connectors. i just have some bad ones here that clearly are short where they should not be.

what problems do you have?

[MyHD120]

Re: Panasonic TCP50GT20

I'm camera shy , and I don't want to come across as a know all but what are you unsure about. Buffer boards I've always been a little low on confidence with but having a look at the block diagram I've posted above a little you can see what pins the inputs are so not a bad place to start. The other thing is to do tha same between the gound plate and the outputs at the panel connectors. i just have some bad ones here that clearly are short where they should not be.

what problems do you have?

This board has been so helpful to amateurs like me. Before posting questions I did a lot of reading, LOT of reading. And watching videos. I've been working on this TV: https://www.badcaps.net/forum/showthread.php?t=26071. I'm just trying to garner more knowledge.

[tw2005]

Re: Panasonic TCP50GT20

This board has been so helpful to amateurs like me. Before posting questions I did a lot of reading, LOT of reading. And watching videos. I've been working on this TV: https://www.badcaps.net/forum/showthread.php?t=26071. I'm just trying to garner more knowledge.

Well this is by far the best forum I've seen and there's a few guys which operate at a quite a high level like Tom and others who are pros. This particular model though I'm spending time on since I have fixed 2 and have an interest in it's issues since I own one and I do expect to have to do anothe SC on the future so trying to get a little stock up on parts.

I'll check out your other post , Vizio is not in my country so generally does not get read but if it's panasonic based then that'll interst me some. generally panasonic is pretty good and my experience is limited.

[MyHD120]

Re: Panasonic TCP50GT20

Man, thank you for your time and interest! Yea, Tom, I don't know how he does it. Does he even sleep? I've never seen a board like this and I've been surfing since the early 90's. The closest board is the AVS Forum. Thanks again.

[tom66]

Re: Panasonic TCP50GT20

I can confirm I just slept 12 hours because early morning lectures were cancelled. It was nice.

[rcpilot82]

Re: Panasonic TCP50GT20

I can confirm I just slept 12 hours because early morning lectures were cancelled. It was nice.

Lucky You, I can confirm I slept only 6 1/2 hours due to my 6 month old not wanting to sleep anymore... I am now at work for the next 9 hours...

The upside for you guys is that I pulled some more measurements. I am not sure if this is helpfull to you. I tested the buffers per the youtube video some time ago and there were no shorts.

Meter set to 2m, one lead to ground. NOTE: the ribbon cables to the screen are connected.

SU41
Pins 1,3,5,7,8,9 all open (meter reads 1)
Pin 2= 1.896
Pin 4= 0.282
Pin 6= the value slowly rose to open.

SD42
Pins 3,4,7,9 all open
Pins 5,6,8, slowly rose to open
Pin 1=1.800
Pin 2=.220

[tw2005]

Re: Panasonic TCP50GT20

That seems comparable to the set i have which I feel is good. Results differ I guess because the range is set to 2Mohms, mine just auto ranges so the slow to rise to open mine heads to 4-6 Mohms. I tested mine completely removed and isolated from each other. I got straight open on SU41 , 6 but SU41, 2,4 & SD42 1,2 are very close to mine. I reckon chances are it's good.

So what was the pin2 short you had? Was that on the SC board or an errror?

[tw2005]

Re: Panasonic TCP50GT20

You would not have pin 8 and 6 mixed in that result on SU41. Pin 8 potentially on that setting may show slowly rising to open. Mine slowly goes to about 6meg pin 8

[rcpilot82]

Re: Panasonic TCP50GT20

That seems comparable to the set i have which I feel is good. Results differ I guess because the range is set to 2Mohms, mine just auto ranges so the slow to rise to open mine heads to 4-6 Mohms. I tested mine completely removed and isolated from each other. I got straight open on SD41 , 6 but SU41, 2,4 & SD42 1,2 are very close to mine. I reckon chances are it's good.

So what was the pin2 short you had? Was that on the SC board or an errror?

My Meter does not autorange. It's just a $17 velleman I have had for years. I believe the short on pin 2 may have been O.E.

I am pretty confident that the buffers are good. I saw no signs of heat or failure on the PS so I feel it is ok as well.

[rcpilot82]

Re: Panasonic TCP50GT20

You would not have pin 8 and 6 mixed in that result on SU41. Pin 8 potentially on that setting may show slowly rising to open. Mine slowly goes to about 6meg pin 8

The paper I wrote everything down on shows pin 6 rising to open and 8 open.

[rcpilot82]

Re: Panasonic TCP50GT20

So out of curiosity, are all the test points (TPxxx) supposed to be grounded on the SC board?

[tw2005]

Re: Panasonic TCP50GT20

Yeah, I think you're pretty right. The cct protection seems to save the PSU. I think you'll find if my memory serves me right that if you have all leads removed from the SC board and you power up it will power the SS, a small green onboard led will come on but only a few seconds and then go SOS7.
I know that's how i started my fault finding and if you backprobed one of the Vs lines you will see VS come up for the same time and then bleed off at shutdown.

I think I also confirm the 15V as well but you probably don't need to test it but can't hurt.
Pretty much how I knew the SOS4 was bogus although correct given when the sc is connected it put a dead short on the PSU so the only code it could spit out.

[tw2005]

Re: Panasonic TCP50GT20

The paper I wrote everything down on shows pin 6 rising to open and 8 open.

has me baffled, rechecked mine and no activity on the meter at all. If you look at the block diagram it shows nothing of importance or any reference to an input at pin 6?

at least not a short. I guess we'll find out when you get it running. I probably won't find out until i install that board which won't happen unless my tv has another blowout.
I have ordered another one to try and get a set again so I'll check it against that one when it arrives.

Shopjimmy got a few more SC boards in , don't expect them to last long.

[tw2005]

Re: Panasonic TCP50GT20

So out of curiosity, are all the test points (TPxxx) supposed to be grounded on the SC board?

I doubt it. Have you downloaded the manual yet? It's going to help you especially if you want to order genuine parts. You'll be able to search the TP locations and see how they interconnect in the schematics.

[rcpilot82]

Re: Panasonic TCP50GT20

I doubt it. Have you downloaded the manual yet? It's going to help you especially if you want to order genuine parts. You'll be able to search the TP locations and see how they interconnect in the schematics.

Yes I downloaded it but I only looked at it real quick. Fixing the blown board is not a top of the priority at the moment. Kinda going to be one of those things that I'll do when I get some free time.

[rcpilot82]

Re: Panasonic TCP50GT20

New board worked BUT now i have 2 horizontal black lines on the screen. They go the whole way across. Any ideas??

[tom66]

Re: Panasonic TCP50GT20

You replaced the SU or SD right? In which case, locate the ribbon for that particular portion which has the defect on the display, unplug it, and reseat it. (You must do this with power off.)

[rcpilot82]

Re: Panasonic TCP50GT20

I reseated the ribbon cables and here is what I have....

[rcpilot82]

Re: Panasonic TCP50GT20

You replaced the SU or SD right? In which case, locate the ribbon for that particular portion which has the defect on the display, unplug it, and reseat it. (You must do this with power off.)

I replaced the SC board (5081AF)only. I removed the buffers to check them and thats it.

[tom66]

Re: Panasonic TCP50GT20

If you removed them, getting the cables back in is very fiddly, and it's hard to do right. You'll have to reseat them all until the picture works better.