Panasonic th-50px77u

[martino]

Hello again
This Panasonic is from a friend,he found out I tinker a bit with TV's and asked me if I would post his TV in here to see if any one knew whats happening..
It's just out of warranty..
Only the bottom halve of the screen is showing...Worked fine,next time he turned it on it was like this....no power searches etc that he knows off..
I do not have the TV at my place,he was more or less hoping one of the experts here would have a general idea what it could be...

[tom66]

Re: Panasonic th-50px77u

SU board or A board.

To rule in/out A board:

Power the TV on.
On the TV, hold the VOL- button.
Press the RECALL button three times on the remote in quick succession.
Wait approximately 10 seconds. Screen may flicker.
Press the "2" button on the remote control twice.
A pattern should appear. Press "2" again to cycle through each.

Do the patterns cover the whole screen, or just the bottom?

[martino]

Re: Panasonic th-50px77u

I relayed this info over to my friend....Am I correct that during the whole test he has to hold down the vol- button..???

[tom66]

Re: Panasonic th-50px77u

No, release it after pressing the third RECALL. Sorry for not mentioning that.
Correction to above: "2" should be pressed each time to cycle not RED.

[martino]

Re: Panasonic th-50px77u

Don't be sorry..!!! I appreciate your time and effort greatly..!!!!!!

[martino]

Re: Panasonic th-50px77u

Friend couldn't get any pattern going...I'm wondering if he's doing it right..Trying to get the TV to my place,much easier...

[tom66]

Re: Panasonic th-50px77u

I'll see if tw2005 turns up he may have a better idea about test pattern mode on these.

[tw2005]

Re: Panasonic th-50px77u

serv menu , then select aging, then cycle through each pattern with the remote I believe.

I expect bad SU would give half screen, but no harm in running the test though.







P.S. Tom, we could do with some help on the 42PX24 10 blink fiasco post.

[tw2005]

Re: Panasonic th-50px77u

Just realised, with no top half he'll have no visibility of the serv menu. quick flick through the training, could also be D board and maybe SC.

Guide I have is called

panasonic_th-42-50px75u_th-42-40px77u_ch_gph10du_troubleshooting

I'm on mobile broadband, trying to save my limit otherwise i'd upload it.

I think you have that in your stockpile Tom.

[martino]

Re: Panasonic th-50px77u

SU board or A board.

To rule in/out A board:

Power the TV on.
On the TV, hold the VOL- button.
Press the RECALL button three times on the remote in quick succession.
Wait approximately 10 seconds. Screen may flicker.
Press the "2" button on the remote control twice.
A pattern should appear. Press "2" again to cycle through each.

Do the patterns cover the whole screen, or just the bottom?

So,I became the proud owner of this tv.......
As per suggestion of Tom66 I ran the test screens....and it only shows up on the bottom halve of the screen,top halve stays dead...
So,does that rule "in" or rule "out the A board? Any suggestions on further testing?
I apologize for non existing pics of the boards,as I just brought it home and didn't pry it open yet

[tom66]

Re: Panasonic th-50px77u

It rules out the A board; the fault is on SU or D, most likely SU.

[martino]

Re: Panasonic th-50px77u

so,the SU board is kinda like a Y-buffer board I take it??
I found a set online for 55 bucks delivered,thinking of buying it...
Hard to repair on component level I take it? Did anybody try that?

[tom66]

Re: Panasonic th-50px77u

They are generally considered unrepairable.
You can replace just the SU.
The SU is equivalent to the upper Y-buffer board.

[elbae1]

Re: Panasonic th-50px77u

I am having the same problem noted in the first post. My TV is 5 years old. Is the SU or D board a hard part to replace? I am somewhat handy but never replaced any TV components. If it is straightforward, does anyone have instructions on how to replace the board and which board I should replace? Thanks for the help!

[martino]

Re: Panasonic th-50px77u

You should do the test as per post#2.
If the test screen is only on halve then you know it's your buffer boards.
Tomorrow I will post some pics of what they look like and how to replace them, it's real easy to do

[martino]

Re: Panasonic th-50px77u

As promised some pic's from the buffer boards...
Replacing is easy,make sure TV is unplugged etc,pretty high voltage around the area you're working..
To avoid static discharge from you to a component,always touch a metal part in the TV before touching a board...
Just look at the pics to locate the boards,they are on the left side facing the gut side of the TV.
It's a few screws,some ribbon cables and plug,took pics of them..
Be careful with the ribbon cables are they are a bit fragile...To unplug them flip up the black clip on the connector(see pic) and carefully wiggle the ribbon out..
When seating the ribbon into new board,make sure it inserts fully and straight without using too much force...

Board numbers are: TNPA4188 and TNPA4189.
They can be bought as a pair for around $30 to $40 bucks....

BUT make sure you do the test pattern as described by TOM66 in post#2 in this thread to make sure it's indeed the buffer boards...

Hope this helps

**not sure why pic's uploaded side way's,sorry**

[elbae1]

Re: Panasonic th-50px77u

Thanks for the help. I just tried the test and the bottom half of the screen would alternate between being solid red, green, blue and white. Every once in a while, the top half of the screen would light up the same color as the bottom half. Does that still indicate a problem with the SU board?

[martino]

Re: Panasonic th-50px77u

Would it light up on certain colours ? Lets say red, would every time red comes around it would also show it on top halve? Or is it random just here and there and a short flash?

[elbae1]

Re: Panasonic th-50px77u

I remember it being more random. I can run it again and check though...Does it make a difference? Is there anything I should pay attention for?

[martino]

Re: Panasonic th-50px77u

If I remember correctly mine did the same thing. Randomly it would kinda flash the top halve as well.
Mine is still on the bench as I'm waiting (3weeks now) for the buffer boards to come in.
I'm 99% sure that will fix it. I will report here what the outcome is. Plz do the same.