Panasonic tc-p50g20 with 10 blinks

[crosstalk]

Hi. I am trying to figure out if I should be troubleshooting the P board or the A board on this one. The troubleshooting chart tells me to replace the A board, but I noticed that I am not getting the expected 15vdc on +15V_S AND P15V. I am getting 15vdc on F+15V.

How do you jumper this power supply on to test it? I have tried connecting, P_S0, P_S1 and TV_SUB_ON to STB5V, but I still don't get +15V_S and P15V. With the A board connected, I see ~3vdc on TV_SUB_ON and ~1.2vdc on P_S0.

[tw2005]

Re: Panasonic tc-p50g20 with 10 blinks

Hi. I am trying to figure out if I should be troubleshooting the P board or the A board on this one. The troubleshooting chart tells me to replace the A board, but I noticed that I am not getting the expected 15vdc on +15V_S AND P15V. I am getting 15vdc on F+15V.

How do you jumper this power supply on to test it? I have tried connecting, P_S0, P_S1 and TV_SUB_ON to STB5V, but I still don't get +15V_S and P15V. With the A board connected, I see ~3vdc on TV_SUB_ON and ~1.2vdc on P_S0.

there's a chance this is shorted SC board.

Here's something I have done in the past.

TV off,

disconnect SC2, SS11, P35, and the 3 white ribbons on the side of the A-board.

Now turn it on, if it turns on and no error blinks the P and A are ok. Do this for less than 30secs.

Turn it off, don't reconnect anything for 5 mins or so.

if no error blink happened, focus on the SC, check SC2 could be short or low ohms, check the P15V line on the SC could be shorted or low.

The P15v feeds the two M81737P FET driver Ics, IC521 is the one that goes, may even have a burn or hole in it.

search tnpa5081, I have a long thread on that board.

often a 10 blink can change to 4 blink if it is the SC. there will be a bunch of parts gone and you may find some repair services out there

[Rickig]

Re: Panasonic tc-p50g20 with 10 blinks

I had this fault. Was sc board.

[crosstalk]

Re: Panasonic tc-p50g20 with 10 blinks

I disconnected SC2, SS11, P35, and the 3 white ribbons. Turns on with no blinks, so I looked at the SC board. I did find a low resistance on Vsus at SC2 for a fraction of a second. The meter reads around 200 ohms then jumps to kOhm range. No short or low ohms on P15V (at TP82). I do get 15vdc on the P15V, so probably not P board as you said.

I also can't find any shorts on either of the two M81737P. I guess something is wrong with the Vsus part of the circuit. I will read the tnpa5081 repair thread to see if I can find the bad component.

[tw2005]

Re: Panasonic tc-p50g20 with 10 blinks

I disconnected SC2, SS11, P35, and the 3 white ribbons. Turns on with no blinks, so I looked at the SC board. I did find a low resistance on Vsus at SC2 for a fraction of a second. The meter reads around 200 ohms then jumps to kOhm range. No short or low ohms on P15V (at TP82). I do get 15vdc on the P15V, so probably not P board as you said.

I also can't find any shorts on either of the two M81737P. I guess something is wrong with the Vsus part of the circuit. I will read the tnpa5081 repair thread to see if I can find the bad component.

Does not have to be a short , just lower resistance than normal.

[crosstalk]

Re: Panasonic tc-p50g20 with 10 blinks

Seems like D711 (near T471) is testing bad in-circuit. I'm not sure how this relates to Vsus other than through IC784. The "source" pins of IC784 are 3.0 ohms to ground.

[crosstalk]

Re: Panasonic tc-p50g20 with 10 blinks

Looks like a lot of the transistors are shorted. Not sure why the Vsus isn't completely dead shorted. I am not sure if I should try to replace all of them or just replace the board.

[Terryfictv]

Re: Panasonic tc-p50g20 with 10 blinks

send to a re-builder / repair service. Search TNPA5081 repair.
Same for TNPA5105. Too many shorts = high degree of difficulty.

[tw2005]

Re: Panasonic tc-p50g20 with 10 blinks

Looks like a lot of the transistors are shorted. Not sure why the Vsus isn't completely dead shorted. I am not sure if I should try to replace all of them or just replace the board.

It does vary board to board what happens at SC2 but overall the parts that fail are usually the same. having had people try following the info I've posted it's 50/50 on success.

If you don't get it right first time it can spiral to a point of not being recoverable as further items can be damaged on a powerup if anything is missed.

[bwreno]

Re: Panasonic tc-p50g20 with 10 blinks

Hi. I've been trying to get my tcp50g20 back in working order but no luck. I'm a nooby and this seems to be the most recent thread so I thought I'd jump in. The TV will shut down and restart at random intervals. It's used as a 2nd TV off satellite so it's fed signal through coaxial in. It fails to recognize signal from satellite but does get signal OTA (But still shuts off on its own). I have tried to use the manual posted here but my TV gives a 13 blink error code and manual only goes to 12. I replaced A board and problem remains, so I reinstalled original. I did measure the 3 voltage points for R as shown in manual and they read fine. Any ideas or suggestions greatly appreciated.

[tw2005]

Re: Panasonic tc-p50g20 with 10 blinks

Hi. I've been trying to get my tcp50g20 back in working order but no luck. I'm a nooby and this seems to be the most recent thread so I thought I'd jump in. The TV will shut down and restart at random intervals. It's used as a 2nd TV off satellite so it's fed signal through coaxial in. It fails to recognize signal from satellite but does get signal OTA (But still shuts off on its own). I have tried to use the manual posted here but my TV gives a 13 blink error code and manual only goes to 12. I replaced A board and problem remains, so I reinstalled original. I did measure the 3 voltage points for R as shown in manual and they read fine. Any ideas or suggestions greatly appreciated.

13 blink would be an A board issue, strange 2 boards doing the same but it's not impossible to get a dud board secondhand so could very well be 2 bad boards. random shutdown and restart sounds like the A board has been heat affected.

All i could suggest is returning the board and see if you can get another

[SpinMaster12]

Re: Panasonic tc-p50g20 with 10 blinks

I have a Panasonic TCP50G20 with the 10 blink error.
I went through a long diagnostic call to confirm it was a bad SC
Board. So I bought a new SC board and installed it.

When powered it up, it worked correctly for five minutes, but the entire time, there was a loud buzzing noise from the SC Board. Then there was a very bright and loud spark from some where on the top left of the SC board and it stopped working.

I thought it was another bad SC Board, so I found another one and just put it in.
BUT when I powered it up, I heard the loud buzzing sound again. I quickly pulled out the power cord before anything else could happen. I don't want to kill another of these hard to find SC boards.

I am guessing there is something, maybe in the POWER Board that is killing the SC board.

How do I test the power board?
Is there anything else I should be looking at?
Has anyone else had this issue?
This is now a 3 month long project and I would be very grateful for Any help.

Thanks!

[tw2005]

Re: Panasonic tc-p50g20 with 10 blinks

One thing which is always important is to resistance check the su and SD boards. How loud is the buzz? Make sure all bolts are in and firm on the sc. Should find a g20,25 guide for the tests or troll through the tnpa5081 thread

[SpinMaster12]

Re: Panasonic tc-p50g20 with 10 blinks

Thanks of the quick response.

The buzzing sound is about as loud as a person humming.
I will double check all of the screws and bolts.

After that, how do I perform the resistance checks?
I have a multimeter and I work in theatrical lighting, so I know basic wiring.

[tw2005]

Re: Panasonic tc-p50g20 with 10 blinks

Thanks of the quick response.

The buzzing sound is about as loud as a person humming.
I will double check all of the screws and bolts.

After that, how do I perform the resistance checks?
I have a multimeter and I work in theatrical lighting, so I know basic wiring.

follow the guide that is already uploaded in this thread which I did not realise was already there. has a whole section on the sc and resistance checks on those boards. An auto ranging meter of good quality would be handy e.g. a fluke or equivalent. the guide tells you the resistance expected but need to measure about 220 k ohms, 1.8-2.1 meg ohms and over 5meg at 3 checkpoints on each board. SC boards can buzz but you would not normally hear it over the TV unless you had no sound and maybe a high brightness screen like white, or you've got your ear close to the TV. If they're not bolted in properly or bolts missing they can make a racket.

[SpinMaster12]

Re: Panasonic tc-p50g20 with 10 blinks

Thanks I will look for the resistance guide.

But is there a way to test if the Power Board may be destroying the SC board?
The last one I put in had a huge spark after running for a few minutes and then was dead?