Panasonic TH-50PX75U Flow chart questions

[coreyand]

I have a Panasonic TH-50PX75U plasma I picked up the other day, I have been through the other threads on this forum and followed the flow chart.

When power is applied and the the power button is first pushed the light remains red for a second then blinks 6 times. After this it blinks 7 times.

I followed the flow chart for the 6 light fix, disconnected SC2, and Sc20. When I turn on the tv the red light stays solid no blinking, but there is this high pitched whining noise that happens intermittently. When the troubleshooting manual specifies if the tv turns on and stays on I am assuming the screen would be back lit and not just a red a light. Eventually the tv powers down meaning the red light goes off, no blinks.

Moving on to the next step for the 6 button blink, it specifies to reconnect SC2 and SC20, and disconnect CN P12 from the P board, SS11, SS34, and SS23(SS33 on my model.) from the SS board. Then place the pin from SS34 on pins 8 and 10 of P12 and turn the tv on.

The result from that is the power light blinks 6 times again the first time, then after that sequence it blinks 7 times.

The next step in the flow char it to reconnect all disconnected connectors back to the SS board CN P12, SS11, SS34, and S33. Remove the A block board to I can get to the D, and C boards.

The next part was tricky, grounding the Base of Q302 to the base of the D board. I get a little confusion here because it does not mention I am to have all the connectors for the A board plugged in or not, and when it mentions ground it to the base of the D board is there a ground place for this or can I just ground it to the screw holding the D board in place. I figure a ground is a ground so I grounded it to the screw. Getting the connector to stay on the base of the Q302 was difficult but I got it, I think.

So the flow chart says to check for 15v on Pin 7 of P7 of the P board. I get nothing, it also says in the same segment to check for the VSUS on P2, before the tv shuts off I get about 192V. Also I get 6 blinking lights, followed by 7 again.

This attempt was with the A board still hooked up, since the directions never said to have it connected or reconnect Ill try again with the A board disconnected right now.

At one point on the pin 7 of P7 I get 3.28VDC and on the VSUS of Pin1 on P2 I get 191VDC.

So it would seem I get the power at the VSUS 190v but not the 15vdc on pin 7 of p7, which the flowchart does not indicate if that happens, one result says the D board is bad and the says the P board is bad. How can I be certain.

Now, I will follow the flow chart for the 7 blink symptom.

It asks to remove SC2, and SC20 which I have done previously and know the result so moving on to the next step.

It says I need to check for 15Vdc on pin 1 of CN P25, I get 15Vdc on this, the next step is to check voltage on the VSUS on pin 1 of CN P2, I get 191V as I did before.

So all of this trouble shooting points to the P board, the D board, and the SS board.

To add a note on the SS board I hear a high pitched noise coming from that general area in all the testing I have done. With all things that I have tested what are you guys opinions? I dont want to order the wrong board if one is available.

[coreyand]

Re: Panasonic TH-50PX75U Flow chart questions

Im bumping this because I need to know which board may be bad to order the replacement, unless it all of the boards?

[tw2005]

Re: Panasonic TH-50PX75U Flow chart questions

very confusing. I don't know how the error code starts at 6 then changes to 7 whilst blinking.never seen that before on a panasonic.

with the first test, no display but TV on is what to expect( no error blinks)

Sounds like it did that, so maybe continue down the Sc,sd,su path for 7 blink if you think it has 7.

Not terribly familar with that series

[coreyand]

Re: Panasonic TH-50PX75U Flow chart questions

Disregarding the chart the first time I plug it into power and press the power button, the button turns red solid for a few seconds, then blinks 6 times. After that it pauses and continues to blink 7 times. I ordered a new D board and SS board for so hopefully that will solve the issue.

Does anybody know if its worth it or possible to rebuilt the SS board so I can find out while I wait for shipping?

[coreyand]

Re: Panasonic TH-50PX75U Flow chart questions

So according to flow chart on the FSM for this tv I have replaced the boards that it said to.

So far I've replaced the D board, the SS board, and the SC board. I still get the same result as I did in the beginning. When I press the power button the power indicator lights up solid red for a second, I can hear the tv trying to turn on, the the power light blinks 6 times, and afterwords 7 times.

Im pulling my hair out on this tv because I have replaced the appropriate boards that the flow chart says to replace. I receive the correct voltages in the places it asks me to test.

I pulled the 3 900qf 220v caps to check those, they read about 850 capacitance each, which is low but I had another set with low reading like this work fine. Besides it is not like the power supply is dead it appears to functioning perfectly fine.

If I remove SC2 and SC20 and turn on the set the power light stays constant but it does not power up the screen, also there is a slight buzzing noise coming from the SS board, This happens on both SS boards - the original and the one I ordered to replace it.

Any suggestions? I hate plasmas...working on them anyway.

[tw2005]

Re: Panasonic TH-50PX75U Flow chart questions

have you tried the next steps

Connect
the connectors SC2(*2),
and SC20 to the SC board. Remove the SU board. Turn the TV on. Does the TV power up
and stay on?

Install
the SU board and
Remove the SD board. Turn the TV on. Does
it power up
and stay on?

(*2) CAUTION:
Before connecting P2/SC2 or P11/SS11, discharge is necessary to prevent potential shock caused by VSUS.

[coreyand]

Re: Panasonic TH-50PX75U Flow chart questions

Okay following the next steps I removed the SU board and tried powering it on, nothing still 7 blinks, however when I removed the SD and powered on the tv the top half came on, oddly split it half and 2 different colors. But its on! I am relieved because I was beginning to think the panel had gone south on me.

Attached is the pictures of what I got, I assume the SD board is bad and will order a new one, however is the screen up top being two different colors like that normal? Is there maybe another issue causing the screen to look this way?

Thanks for your help guys I was really going for broke on this tv, ordering so many parts with no change ect.

[coreyand]

Re: Panasonic TH-50PX75U Flow chart questions

Okay quick update, the tv no longer powers up and stays on like in the above photos. Ive changed nothing. The first time it powered on for long enough for me to get the right lighting and least reflective light in the picture to take it, now it only turns on for a second and then shuts off. Suspecting the SS board I put the replacement board I ordered back in the tv with no avail. The SC board is still the new one I ordered. Im unsure if I left the new D board in the tv or put the old one back.

So a little progress with a few more problems.

[tw2005]

Re: Panasonic TH-50PX75U Flow chart questions

turns on, shuts off, but what code? unfortunately it may be bad panel or both buffers were bad and potentially inadvertantly killed the SC?

[coreyand]

Re: Panasonic TH-50PX75U Flow chart questions

The same 7 blink code before, but NOW it wont even turn on, it blinks before I can push the power button. I put things back to how I had them previously by reconnecting the SD board and such, I end up getting an 8 blink code error now. Sometimes a 7 blink code error, and also a 6. Its like this tv has seen better days...

When I unplug the SC, and SS board and place SS34 jumper where P12 is on the last pins as it instructs the tv then turns on. Not the screen but the red led stays lit.

Im thinking of swapping the old SC board back in but im hesitant to do so if I indeed burned up this one.

Any suggestions?

[coreyand]

Re: Panasonic TH-50PX75U Flow chart questions

I put all tv connections back like their supposed to be and what happens now is the 7 blink error as it was in the beginning. Repeating the steps again of disconnecting SC2 and SC20 and trying to power it on I get an 8 blink error, where as before the light would stay solid red.

So now it would seem the SS board is being faulty. I happen to have an extra one of those. I will install and update momentarily.

[coreyand]

Re: Panasonic TH-50PX75U Flow chart questions

Alright installing the other SS board and having everything connected I get the 7 blink error when attempting to turn on, next I disconnect SC20 and SC2 and the power led remains on. Going through the same trouble shooting steps as before I will now next remove the SU board first, and then the SD board(I assume this is already the troublesome board)

Okay, I troubleshoot all the way to removing the SD board which seems to be the for sure issue, I get a different picture this time. Ive attached photos. There is however a small area to the left that has purple lines running vertically. I imagine this may be as simple to fix as reseating some of the ribbon cables.

Before I do anything stupid or unnecessary I will wait for a suggestion from somebody on here and order a replacement SD board.

Thanks in advance guys.

[coreyand]

Re: Panasonic TH-50PX75U Flow chart questions

Okay, I reseated some ribbon cables and the purple lines are gone. I just ordered the SD board from ebay for $20. It should be here by next friday. I will keep you guys posted with the progress.

How weird the tv gave me so many different error codes, and the problems started acting differently. Either way the new part, and the 4th board I have ordered so far on this tv is on its way.

Thanks for all your help. Will post after new part is installed.

[coreyand]

Re: Panasonic TH-50PX75U Flow chart questions

I got the replacement SD board in today,

First I verified that the top half of the the tv would still work, and it did just as I had left it. Then proceeded to replace the SD board, plugged everything in and turned on the set. The entire screen powered up for a fraction of a second followed by a bright flash more concentrated on the bottom of the tv and then the good ol' error codes started flashing at me.

Im at a loss here guys what could this mean, what else could I dump more money into to fix this problem?

Thanks, Corey.

[coreyand]

Re: Panasonic TH-50PX75U Flow chart questions

Any ideas, I unplug the SD board and it goes back to the top half of the screen working. Plugging the new SD board back in it goes back to the 7/6 code error. Is it possible that part of the lower screen is broken where I cant see it causing it to short out the SD board as soon as I power it up, because I feel like the SD board is shorted out now but Im not for sure.

Thanks for the help guys.

[newtothis]

Re: Panasonic TH-50PX75U Flow chart questions

To me it seems you have a fracture to the panel resulting in a short

[coreyand]

Re: Panasonic TH-50PX75U Flow chart questions

I was thinking the same thing, causing the SD board to short out, which means all the money Ive dumped into this thing is a lost cause. Would make sense because the SD board is controlling the bottom half of the screen where as the top half is fine. I think thats going to be the cause, I wont know for sure until take the front plastic piece off and inspect the screen. Which I will do later I have other tvs to work on right now.

[coreyand]

Re: Panasonic TH-50PX75U Flow chart questions

Just...before I chunk this tv, well I mean Im gonna sell the parts it had which I assume are good, and the replacement parts also which Im sure are still good, minus the SD board on ebay. Does this sound logical that the bottom of the panel is cracked somewhere causing the SD board to burn up? It wouldnt be the C1,2, or 3 data driver boards?

[coreyand]

Re: Panasonic TH-50PX75U Flow chart questions

Anybody?

[tw2005]

Re: Panasonic TH-50PX75U Flow chart questions

Anybody?

too hard basket. If the SD was checked prior to install then we may have a better idea. Questions are, was the SD also defective on receipt, if so it should not have been installed.

Was it good, was the small ribbon between the sd and su connected? if so, it puts a big question on the panel having a defect or short in the bottom half.

I don't know of any way of checking the panel, so comes down to risking more money on another SD and is the Sc board ok still?

I think there has been the odd case of panel blowing boards, that's the risk of buying something you know nothing about it's full history.

for all we know, the previous person may have already tried replacing buffers and called it quits??