Panasonic TH-42PX60U With distorted picture

[ecking767]

I was given this Panasonic Plasma TV in non working from a local home theater install company. The unit power off / on with no problem. But the picture is coming on with distortion. I have downloaded the service manual and read it and found nothing related to my problem.

What I have done so far was:

I made voltage measurement all in spec.

Next I started with the buffer board. There is 5 of 74VHCT541AT on each board. swap the 5 74VHCT541AT on one side of board to another and the pattern on the screen swap placed. I couldn't see the menu before the chip swap.So I order from Mouse 10 of these 74VHCT541AT.



I haven't repair any plasma before but I have work on many LCD monitors and LCD TV. any advise will be helpful

Thanks
ecking767

[Th3_uN1Qu3]

Re: Panasonic TH-42PX60U With distorted picture

Well have you swapped the ICs you ordered?

[ecking767]

Re: Panasonic TH-42PX60U With distorted picture

Well have you swapped the ICs you ordered?

Not yeah most likely tonight or this weekend..

[ecking767]

Re: Panasonic TH-42PX60U With distorted picture

UPDATE: After replacing all 10 of the 74VHCT541AT the picture have improved some but I still have a section of missing picture. Also I have a two pink strips on the screen. I'm going to do more measurements on the buffer board and read the service manual some more. I also excess the test menu and all boards pass.

any input will help
thanks
ecking767

[crepiduse]

Re: Panasonic TH-42PX60U With distorted picture

Is the screen cracked in the middle? Looks like it.

[kevinallein]

Re: Panasonic TH-42PX60U With distorted picture

Hi, seems like the second column looked OK in your first picture and has some distortion now after replacing the drivers - is that correct ? This would kind of indicate, that either the new driver has some problem (bad solder, some flux left, ..), or maybe there is a timing sensitivity and different manufacturers of the buffer with slightly different timing make a difference ? Did you have replacement drivers from a different semiconductor manufacturer ?
Also, the column right of the middle of the screen has problems before and after the swap. Did that same section never work correctly at any stage ?

[Wizard]

Re: Panasonic TH-42PX60U With distorted picture

These vertical strips or lines what kind of driver IC looks like (at bottom) is they are replaceable or is bonded to the panel. I see 3 devices failed.

Cheers, Wizard

[ecking767]

Re: Panasonic TH-42PX60U With distorted picture

These vertical strips or lines what kind of driver IC looks like (at bottom) is they are replaceable or is bonded to the panel. I see 3 devices failed.

Cheers, Wizard

I lost to which 3 chips you are referring too. on the SD and SU board (picture 4 of 5) those chips are glue to the board. I will have to replace the whole board.

[ecking767]

Re: Panasonic TH-42PX60U With distorted picture

Today I pick another Panasonic TH-42PX60U with power up fine but only 90% of the screen show a picture. Between the plasma I should be able to determine whats going on. Either bad PDP screen or bad boards. Tonight I will be doing some board swapping.

[ecking767]

Re: Panasonic TH-42PX60U With distorted picture

Hi, seems like the second column looked OK in your first picture and has some distortion now after replacing the drivers - is that correct ?

That correct. I apologize for not posting the actual problem of this plasma TV.

This would kind of indicate, that either the new driver has some problem (bad solder, some flux left, ..), or maybe there is a timing sensitivity and different manufacturers of the buffer with slightly different timing make a difference ? Did you have replacement drivers from a different semiconductor manufacturer ?

Yes, Mouser didn't have the original part I need in Fairchild so I order On Semiconductor replacement. I over look the speed of the replacement. Which was slower. But its strange how It made the screen show a picture.

Also, the column right of the middle of the screen has problems before and after the swap. Did that same section never work correctly at any stage ?

No, I never got a picture in the middle section .I will post a picture tonight of how the screen displaying a picture

I think the screen is bad. I have swap board from another unit and same problem is still there. So I will sale the parts inside.

[ecking767]

Re: Panasonic TH-42PX60U With distorted picture

After the C1 & C2 swapping board, THIS put the TV back to the original problem. I have concluded the panel is bad

[Remeniz]

Re: Panasonic TH-42PX60U With distorted picture

With vertical problems like this I check the X boards/Address boards. They run along the bottom of the plasma panel.

[ecking767]

Re: Panasonic TH-42PX60U With distorted picture

With vertical problems like this I check the X boards/Address boards. They run along the bottom of the plasma panel.

Are you referring to the SCAN Board TNPA3812 & TNPA3813. I brought them both off of eBay and I have another Panasonic TH-42PX60U that display about 90% of a picture on the screen. I will post picture of the 2nd unit problem tonight. Between the two units I wasn't able to get a clear picture either.

[Remeniz]

Re: Panasonic TH-42PX60U With distorted picture

Yep, those are the boards, C1 and C2 data boards in the manual.

Double check the connections from the data boards to the PDP and from the D board (Format Converter/Plasma AI/Sub-Field Processor board) according to the manual, to the data boards. This is the area of the problem.

[ecking767]

Re: Panasonic TH-42PX60U With distorted picture

Yep, those are the boards, C1 and C2 data boards in the manual.

Double check the connections from the data boards to the PDP and from the D board (Format Converter/Plasma AI/Sub-Field Processor board) according to the manual, to the data boards. This is the area of the problem.

OK, I will re-check those connection later. I spend a lot of time boards swapping between the two units. I was hoping to narrow down which board or boards was causing the problem. I will also try cleaning these connection going to the data board and Format Converter/Plasma AI/Sub-Field Processor board.

The picture below is of the second unit I have acquire. 90% of the screen shows a picture.

[edtv]

Re: Panasonic TH-42PX60U With distorted picture

same problem here...surely I hope it's not the panel!!! Anyone seen this lately? Need service manual if any knows where I can download one?

[Toasty]

Re: Panasonic TH-42PX60U With distorted picture

http://elektrotanya.com/

[AndrewMcBride]

Re: Panasonic TH-42PX60U With distorted picture

Does anyone how to fix this. My Panasonic 50" TH-50PX80U can a few small vertical lines through it.
Thanks

[tw2005]

Re: Panasonic TH-42PX60U With distorted picture

I had a 42PX70 with this and as far as I could work out it's the drive ic on the panel tabs, not repairable. swapped the c boards , digital board and main boards from another which had no issue and fault remained.

[almightymopy]

Re: Panasonic TH-42PX60U With distorted picture

I also have a panasonic th-42px60u but my distorted picture is a little different i have replaced the ysus and xsus board i am providing images these images shown is a xbox connected to the tv via hdmi..