panasonic tv fault with 4 blinks

[vanpham]

Hi All,
my tv model is Panasonic plasma TH-P50VA20A. It got 7 blink fault and the repairer said that it was the SC circuit board fault but he does not have part for it.
The SC circuit board was TNPA 5081 AF. I managed to find a similar SC board model TNPA 5081 AY (it comes with the other two boards attached to it, sustain and buffer). I replaced my faulty one with the one I just purchased (the whole set of three).
However, now I have four blink fault. Is it suggesting a power board fault? is there a way I test it?
When I unplugged the connections to the SC board, I then got 6 blinks. When I plugged them back in I got 4 blinks again.
I attached here the photos of the
SC/sustain/buffer set, power board and the whole back of the TV photos.
Thank you very much in advance for your help.
I have read other posts here but have not been able to figure out what to do.
Van.

[Andrew F. Ali]

Re: panasonic tv fault with 4 blinks

Here is away to self test the P Bd so you can be absolutely sure it is good.
Build a test-jig by connecting two (2) 220V 100W light bulbs in series so that the two (2) wire ends can be connected to a circuit.
Follow these steps in order:
1. Disconnect all the connectors to the P Bd, except the AC input connector.
2. On connector P7 connect a1kOhm resistor across pin 1 (StBy 5V) and pin 5 (F-StBy-ON).
3. Connect another 1kOhm resistor across pin 1 (StBy 5V) and pin 7 (Panel-Main-ON).
4. On connector P35 connect a wire to bridge pin 1 and pin 3.
5. Connect the test-jig across connector P2 ( Vsus output voltage and chassis GND).
6. Apply the AC and the test-jig should light up.
7. Measure the DC voltage across connector P2, it should read approx. 192 Vdc.
8. Observe the intensity of the test-jig. If it starts to dim then there is a problem with the P Bd. If the intensity remain then the P Bd is OK.
9. Measure the other output voltages on connector P7 15Vdc etc. (Nerves of steel required)

NB: a. Be careful not to short any pins on P7 when making solder connections.
b. Look at the connections for shorts and rectify before applying AC.
c. be careful DMM probes do not slip while making voltage readings.
d. If Step No. 8 passes the test then confidently diagnose the A Bd as defective.
Good Luck and remember BE CAREFUL!!

Andrew F. Ali is online now Report Post

[vanpham]

Re: panasonic tv fault with 4 blinks

Hi Ali,
Thanks for your instruction on my problem. As I was not confident in carrying out the steps I have gone and found a power board and replaced it but I still got a 4 blinks so I assume that the P board was not the problem.
Please could you suggest the next step. YOu did mention about the A board, is there a way to check it.
Thanks in advance for your help
Van.

[tw2005]

Re: panasonic tv fault with 4 blinks

Hi Ali,
Thanks for your instruction on my problem. As I was not confident in carrying out the steps I have gone and found a power board and replaced it but I still got a 4 blinks so I assume that the P board was not the problem.
Please could you suggest the next step. YOu did mention about the A board, is there a way to check it.
Thanks in advance for your help
Van.

Sorry , I must have missed this thread.

Going on what you describe you have a TH-P50V20A

The SC board you have used is from a TH-P50VT20A or equivalent 3D model - not compatible. both the SC and SD boards are different circuitry.
What you received may have been faulty anyway, not sure what happens when you put the wrong boards in and I'm not going to try it in mine for fun either. I hate to think how many $$ you've sunk into this if you've used a technician, paid for a SC/SD/SU set and now a P-board unless you got lucky and found a junked TV and pulled the boards.

A Shorted SC board, shorts P board on the Vsus (sc2) triggers SOS4. That's generally the most common way these die. Might be worth starting from scratch with your original boards, you can forget about continuing from where you're at now because you have the wrong boards.

Check and confirm across SC2 is short on that new SC board, then pull that whole set out.

Do you still have your original SC/SD/SU boards? I hope the repairer gave the original SC back.

Try and take photos at a resolution that can be zoomed in and in focus. Not sure if you've used a phone but the res is so bad I can't make out any bolts to tell if they're in or out

[vanpham]

Re: panasonic tv fault with 4 blinks

Hi Ali,
Thanks for your help,
I have attached here the SC board and the P board taken using a camera.
I still have my original board as shown in the photo.
Please let me know what to do next.
Thanks
Van.

[tw2005]

Re: panasonic tv fault with 4 blinks

Hi Ali,
Thanks for your help,
I have attached here the SC board and the P board taken using a camera.
I still have my original board as shown in the photo.
Please let me know what to do next.
Thanks
Van.

If the replacement p board is identical part number as the original then it may has well be left unless you can return it and get some money back.

Did you check out he AY revision SC and see if Sc2 was shorted out?

The tech has stated Sc is bad, 7 blink but let's not assume.

You can
a. go to that guide and locate the resistance checks for the sd/su boards and see what you get, they'll need to be isolated from the SC and each other. A decnt meter that can autorange and get to about 6 megohms would be handy

b. re-install the SC without any buffer boards, make sure the board is bolted in, i.e earthed, sc20 and sc2 leads connected

make sure all other boards and leads are connected as normal.

on the SC, there is a 2 pin connector SC50, short those pins together, then turn the Tv on and see what blink code it gives or if it goes solid green.

This is test is also outlined in that guide

let us know

[tw2005]

Re: panasonic tv fault with 4 blinks

That's reinstall the correct SC rev AF for testing.

and your old buffer boards also test resistance

[vanpham]

Re: panasonic tv fault with 4 blinks

I have removed the AY board and put back my old one and when I tested the SC2, (the brown cable terminal) I got large resistance. The white cable terminal shows 0 ohm.

The P board is also of different number and I have removed it and put back my old one.


I did a quick resistance test today (as described in the table on page 8 of the document)and found that the resistance at P11/Brown (pin 4/voltage P15V) is less than 1k. The other two tests: P11/white and P35/White show resistance much greater than 1kohm.

The manual describe the steps for further test when P11/Brown (or P15V) is shorted (page 10). Should I follow those steps

I will also try to do the steps you suggested.

thanks heaps
Van.

[tw2005]

Re: panasonic tv fault with 4 blinks

I have removed the AY board and put back my old one and when I tested the SC2, (the brown cable terminal) I got large resistance. The white cable terminal shows 0 ohm.

The P board is also of different number and I have removed it and put back my old one.


I did a quick resistance test today (as described in the table on page 8 of the document)and found that the resistance at P11/Brown (pin 4/voltage P15V) is less than 1k. The other two tests: P11/white and P35/White show resistance much greater than 1kohm.

The manual describe the steps for further test when P11/Brown (or P15V) is shorted (page 10). Should I follow those steps

I will also try to do the steps you suggested.

thanks heaps
Van.

With SC2, just measure across those 2 pins( 1 probe on each), I need to know how good the meter is. prefer this info first and reading of both boards please. can the AY set be returned for refund? Was it local or from OS?

With 7 blink just head to that section but if you can test the buffer resistances and do that SC50 with buffers removed that should expedite this.

It will be 1 , 2 or 3 of those boards, won't be P, unlikely A

Then I'll have you prove A & P in one go to satisfy that you don't have 4 blink bad P or bad A(that's the plan)

You're 1.5 hours behind me so my eyes are getting tired if you want to get through this tonight.

[vanpham]

Re: panasonic tv fault with 4 blinks

SC2 for my old board was 765 ohm, for the AY board was 0ohm (disconnected from the tv). I can return the AY board as it is local.
Thanks. Sorry for this.

[tw2005]

Re: panasonic tv fault with 4 blinks

SC2 for my old board was 765 ohm, for the AY board was 0ohm (disconnected from the tv). I can return the AY board as it is local.
Thanks. Sorry for this.

yeah, ok. so the Ay board is your 4 blinker, dead short on the Vsus

765 ohm is bad, what range is the meter set to or is it auto ranging?

Typically you'd see 300 k ohms on first probe, take them off then probe again and it can then change to megohms.

On your AF, Q661, it's a RJP63F3A are those legs shorted when you probe any 2 legs? heatsink with 2 transistors next to Sc50 connector

[vanpham]

Re: panasonic tv fault with 4 blinks

Yes,the Q661 was shorted.
I will try to isolate the buffer boards to check if only the Sc board is faulty.
Thanks a lot for your help.
PS. regarding the AY board, I got it from a local tv repair guy and he is ok for me to return it.
Thanks again.

[tw2005]

Re: panasonic tv fault with 4 blinks

Yes,the Q661 was shorted.
I will try to isolate the buffer boards to check if only the Sc board is faulty.
Thanks a lot for your help.
PS. regarding the AY board, I got it from a local tv repair guy and he is ok for me to return it.
Thanks again.

If Q661 is definitely shorted then not necessary but will at least 100% confirm bad SC, buffer tests are the next important step, then you'll have trouble getting a SC cheap now. not sure what I have

TNPA5081 AF,AP & AW will work but the only revision we had here was AF

[tw2005]

Re: panasonic tv fault with 4 blinks

If you want to confirm A & P are ok this is what i do. disconnect Sc2,SS11, P35, 3 white ribbons at the A board. now turn on, should see the TV start blinking green then lock on solid. that's a pass , don't run for more than 30 secs or it will shutdown with maybe a 4 blink due to no load on th P board.

don't connect any of those leads again for at least 5 mins so the power bleeds off or you can spike the boards especially P35 which feed to the panel via the C boards and will not then be repairable

[vanpham]

Re: panasonic tv fault with 4 blinks

Hi TW2005,
it is a while but I just got an sc board from another repairer. the board is of the same model as mine (TNPA5801 AF). I put this one in and now what I got is horizontal lines on the screen. I would appreciate your suggestions.
Thanks
Van

[tw2005]

Re: panasonic tv fault with 4 blinks

Note where the lines are, turn it off, go to the panel ribbon that corresponds to the lines , lift the latch , reseat that ribbon and make sure it is straight and all the way in.

common problem, most of us have taken a few goes to get this right. You will feel the ribbon wedge then goes in just that little more .

Never do this with the TV running

[vanpham]

Re: panasonic tv fault with 4 blinks

I did what you suggested and it now works. Thank you very much for your guidance.
You are the best!.

[Roj.]

Re: panasonic tv fault with 4 blinks

Hello Vanpham (and anyone else)

Please advise the names/addresses of the repairers who have provided useful Panasonic boards. I'm still looking for an A board for my TH-P54V20A (13 blinks, no external audio problem)

Thanks,
Roj

[vanpham]

Re: panasonic tv fault with 4 blinks

Hi Roj
I got the board via a post on gumtree. A repairer saw it and contacted me.
These are old boards they collected them along the way so sometime they may have what you need.
The one that I got from was Murray in South Perth (111 Angelo St).
I suggest you put an ad on gumtree and if they have they will contact you.
good luck
van.

[Roj.]

Re: panasonic tv fault with 4 blinks

Hello Vanpham

I tried through gumtree a month or so back but will try again

Thanks
Roj