Panasonic viera tv help

[bikemech]

just bought this CHEAP!!
Can anyone help with the rolling horizontal lines,
It does power up and function but has lines rolling down the screen, thanks guys,

 

[chopnhack]

First thing I would do is download a schematic if you can find one. I had a similar problem on a Acer monitor that turned out to be a bad capacitor - this is a frequent mode of failure with electronics. The caps filter the power supply coming into the remaining circuitry. Bad signals coming through can affect a whole lot of functions. Start with opening the case and looking for obvious signs of cap failure: venting (top of metal cap either bulged or open, leaks (electrolytic fluid stains or drips coming out of the cap case)). Less obvious would be signs that the case has swollen slightly and sometimes you would see that at the bottom seal.

 

[chopnhack]

Here's a link, if you sign up for their forum, you can download the service manual: http://www.badcaps.net/forum/showthread.php?t=26584&page=3

 

[bikemech]

Thanks for your reply, I have the back off already and looked at the caps, can't see anything obvious, any ideas which board to start looking at as there is a few in this set, I don't think its the psu as it powers up and works, could be wrong tho, will upload some pix of inside, thanks again

 

[chopnhack]

Thanks for your reply, I have the back off already and looked at the caps, can't see anything obvious, any ideas which board to start looking at as there is a few in this set, I don't think its the psu as it powers up and works, could be wrong tho, will upload some pix of inside, thanks again

I would certainly start at the psu! Just because it powers up doesn't mean the power is stable enough. Yes, pics are good

 

[bikemech]

And ok will look at the psu first.

 

[chopnhack]

Sorry mate, but we will need tighter pics with better lighting to see any defects.

 

[davenn]

Sorry mate, but we will need tighter pics with better lighting to see any defects.

and sharp ... not blurry

 

[bikemech]

I don't think there is anything obvious, I can do better close up pix , where do you want them of?
Shal I start with the psu? Also going to try find a schematic,

 

[bikemech]

are these any good?

 

[bikemech]

i have the service manuel but dont know hot to post it on here??

 

[chopnhack]

Do you have a google account? If you do, you can upload it to your G-drive and make it a public link and send us an invite link or post the invite link here. I am sure other similar services would work.

 

[bikemech]

Thanks for that, will sort that out in the next couple of days, as its New Years eve and I have a few drinks with my name on them, haha , happy new year to everyone and speak soon , Pete.

 

[davenn]

happy new year Pete

 

[bikemech]

And ok will look at the psu first.

can anyone outline what board is what for me please,

am i right in saying the long ones along the length of the screen are the buffers?? (have no idea what there for)

i know centre brown one is the power supply board,

 

[bikemech]

the service manuel is available here, but you have to wait 30 seconds or so for the link to be active, its just underneath the image on the left, it will say processing untill its ready for download

http://elektrotanya.com/panasonic_tx-p42s20_tx-p46s20_tx-p50s20_sch.pdf/download.html

 

[bikemech]

ok so been doing some digging around and been advised it is probably the y-sustain board,
middle of bottom pic post #6
any ideas if this sounds right, thinking of removing it and testing some of the componants?
good idea?
bad idea?

 

[chopnhack]

A likely place to investigate, just be careful of those ribbon cables, they are very delicate! I have had limited success with pulling them out. Sometimes you need a good pair of pliers, but pad the jaws with some duct tape.

 

[bikemech]

i have the y-sus board removed, but all the caps look fine, no damage or swelling anywhere,
could it be a faulty transistor or something else causing this fault,
possibly even bad connection,
the ribbon cables came away fine once i released the little latch on the sockets

 

[chopnhack]

i have the y-sus board removed, but all the caps look fine, no damage or swelling anywhere,
could it be a faulty transistor or something else causing this fault,
possibly even bad connection,
the ribbon cables came away fine once i released the little latch on the sockets

Good job! Alas, I won't be of much further use. Perhaps a more experienced member will be along soon ;-)