Panasonic TC-p46ST30 Partial Horizontal Red Line

[amj]

hi,

Would appreciate any help in regards to an issue I'm having with my Panasonic Tc-p46ST30.
At random times a partial red line will appear. It is always horizontal and always at the same position in height on the screen.

While trying different settings with the tv I noticed that when I increased the Brightness level from 61-68 the line would fade away. At 68 it would be gone.

Also noted that increasing the panel brightness from Med to High made the red line worse.

Any help would be greatly appreciated. Would like to find a fix to the set as it is only a few years old.

amj

[tw2005]

Re: Panasonic TC-p46ST30 Partial Horizontal Red Line

That's something I have not seen here yet. i'm thinking along the lines of panel fault.

A fault on the buffer I'd expect across the full width, A fault on the A board usually digital bars evenly across the panel but that looks localised and the fact brightness makes it disappear suggests panel to me.

I'd get other opinions but unless you have a suite of boards lying around for this to swap out, very hard to pick which board and way too expensive to just take a punt.

I'd try reseating the buffer ribbon, maybe replace the board (SD) if it was cheap , check all screws that mount the sc,sd,su are firm as they work loose and arc although I don't think that's the problem

[tom66]

Re: Panasonic TC-p46ST30 Partial Horizontal Red Line

I would doubt panel. Haven't partial red and blue lines been linked to main boards before?

[tw2005]

Re: Panasonic TC-p46ST30 Partial Horizontal Red Line

I would doubt panel. Haven't partial red and blue lines been linked to main boards before?

When they appear like a barcode in blocks of red and blue evenly spaced ,yes. never seen this though.

even appears to be a red dot on that lady too.

guess we could try test patterns or something. gonna be potentially an expensive trial and error I think.

changing brightness making it disappear , i would have expected it to stay.

[tom66]

Re: Panasonic TC-p46ST30 Partial Horizontal Red Line

Due to how the panel pixels are laid out... R..B..G.. (on these sets) I can't see any way a panel fault could cause this (it would have to skip the other colours repeatedly).... then again I suppose we've seen similar artifacts on LCDs so it's not entirely out of the question, I just personally doubt it.

[tw2005]

Re: Panasonic TC-p46ST30 Partial Horizontal Red Line

Due to how the panel pixels are laid out... R..B..G.. (on these sets) I can't see any way a panel fault could cause this (it would have to skip the other colours repeatedly).... then again I suppose we've seen similar artifacts on LCDs so it's not entirely out of the question, I just personally doubt it.

True, but where do we start? reseat ribbons on buffers and maybe A board?

Certainly something different for a panasonic fault.

[tom66]

Re: Panasonic TC-p46ST30 Partial Horizontal Red Line

Could be bad video RAM, for the panel controller portion. Test patterns might rule it out.

[amj]

Re: Panasonic TC-p46ST30 Partial Horizontal Red Line

Thanks to all for your input. It's appreciated.

FYI, I did have the set open and did tighten any loose screws. Was surprised by how many were a little loose. Also, I did reset any ribbons I could access.

That made no difference.

Just a few other observations. I have a directv HR34 DVR. If I rewind and play back a show which just showed the red line it will appear at the same time and place on the screen when I play it back.
Thought it may be an issue with the DVR, however the line does appear also while using the DVD player.

Another setting which made the issue worse was when I increased the Blk. Ext. setting on the Panasonic.

You mention test patterns, could anyone direct me to them? Would they be patterns I could play from the SD input?

Thanks for all your time and help.
amj

[tw2005]

Re: Panasonic TC-p46ST30 Partial Horizontal Red Line

Thanks to all for your input. It's appreciated.

FYI, I did have the set open and did tighten any loose screws. Was surprised by how many were a little loose. Also, I did reset any ribbons I could access.

That made no difference.

Just a few other observations. I have a directv HR34 DVR. If I rewind and play back a show which just showed the red line it will appear at the same time and place on the screen when I play it back.
Thought it may be an issue with the DVR, however the line does appear also while using the DVD player.

Another setting which made the issue worse was when I increased the Blk. Ext. setting on the Panasonic.

You mention test patterns, could anyone direct me to them? Would they be patterns I could play from the SD input?

Thanks for all your time and help.
amj

Well the rewind to get the exact same result is interesting. That suggests potentially A board to me and Tom's leaning along that way too. Can you watch TV via a normal antenna and see if it occurs doing that?

What you need to know are in the docs. The service manual will tell you how to get into service mode

[amj]

Re: Panasonic TC-p46ST30 Partial Horizontal Red Line

Thanks for the files. No expert in the field here, but will educate myself with the info your provided.

Since the red line does only appear at random times, it will take me some time to try to catch it while watching somethig OTA.

Since increasing the brightness I haven't seen the line. I may just wait this out a bit and see if it gets progressively worse with time.

amj

Well the rewind to get the exact same result is interesting. That suggests potentially A board to me and Tom's leaning along that way too. Can you watch TV via a normal antenna and see if it occurs doing that?

What you need to know are in the docs. The service manual will tell you how to get into service mode