Wide Black Vertical Line Samsung Plasma NOT Panel

[mmartell]

Before I repaired the ymain and buffers on this set (hp-t5054) I broke two caps off the e-buffer when removing the mainboard assembly to get to the control board. I just replaced the two caps and the problem remains.

The line is where I would guess the addressing begins (on the left) but the broken caps were on the center right of the address board when looking at the screen. In other words not in the direct vicinity of the fault.

Is the affected E-Buffer to blame for this or can the Control Board cause this as that was replaced as well ?

(Hard to see the affected area because it blends with the black frame but the light is shining on it in the second pic)

[tom66]

Re: Wide Black Vertical Line Samsung Plasma NOT Panel

If you broke the caps could you have damaged the PCB?
Can still be panel .... unlikely though as you mention, would be a bad coincidence. Did you have it working before?

[tw2005]

Re: Wide Black Vertical Line Samsung Plasma NOT Panel

Be careful with the power lead to those bottom buffers. this is the panel i killed reconnecting that , large arc and destroyed the TV due to residual voltage.

Pictures of the board? There are buffer ICs on tha board. i have the F buffer in front of me and they're mounted midway. maybe one of those is damaged. The drive signal pass through those.


HB541(SN74AHCT541) very common, find on main boards, buffer boards, y and maybe x if you wanted to experiment changing one. Not a bad size to work with

[tw2005]

Re: Wide Black Vertical Line Samsung Plasma NOT Panel

Isn't it the F buffer that drives the left side you say has the black lines?

[mmartell]

Re: Wide Black Vertical Line Samsung Plasma NOT Panel

I want to say it wasn't always like that but can't be sure. Though with the Y buffers in and out of the set I think I would have noticed the bar if it were there.

Can a control board fail in this fashion ? When I get some time I will have a closer look at the E Buffer.

[mmartell]

Re: Wide Black Vertical Line Samsung Plasma NOT Panel

Exactly my point. I thought each of the address buffers was responsible for a half of the screen and the faults are opposite !

[tw2005]

Re: Wide Black Vertical Line Samsung Plasma NOT Panel

Exactly my point. I thought each of the address buffers was responsible for a half of the screen and the faults are opposite !

I don't understand

The black bar is on the left?(I can't make it)

The F buffer drives the left?

I don't think the E or those caps would have anything to do with it.

If the buffer was spiked , could produce a black bar, that is what happened to me but mine was not at the very edge.

I guess missing signals anywhere along the path could do it. Never traced these I guess an oscilloscope would be needed.

I'll take the back seat on this one

[mmartell]

Re: Wide Black Vertical Line Samsung Plasma NOT Panel

Right. My assumption is that the address buffers work similar to the Y buffers in that a fault would be localized to the area served by the buffer which is not the case here. Perhaps the address buffers don't work that way.

I don't remember disconnecting the connector to the F buffer as I had no reason to do so.

[tom66]

Re: Wide Black Vertical Line Samsung Plasma NOT Panel

It is possible for the control board to cause this fault on some earlier panels. Not sure about this one. On newer panels it's very unlikely. Picture of the control board?

[mmartell]

Re: Wide Black Vertical Line Samsung Plasma NOT Panel

Right here, tom.

http://www.shopjimmy.com/media/catal...bn9606522a.jpg

[tom66]

Re: Wide Black Vertical Line Samsung Plasma NOT Panel

That's a newer generation (no logic buffer ICs) so I'd say that wouldn't cause the fault.

[mmartell]

Re: Wide Black Vertical Line Samsung Plasma NOT Panel

Ok so E or F buffer. Is each buffer responsible for one half of the screen or do they not work like that ?

[tom66]

Re: Wide Black Vertical Line Samsung Plasma NOT Panel

Yes they are responsible for each half but they really are only data buffers. They do not process the video in any way. Just provide power (Va ~60VDC, Vcc ~5VDC/~3.3VDC), clock, data and reset signals..

[mmartell]

Re: Wide Black Vertical Line Samsung Plasma NOT Panel

But I clobbered the caps on the E buffer and the picture fault is on the opposite side so to boil it down I have a problem with my F Buffer or I may in fact have a bad panel.

[tom66]

Re: Wide Black Vertical Line Samsung Plasma NOT Panel

I think F-buffer or panel at fault here. Probably unrelated damage.

[mmartell]

Re: Wide Black Vertical Line Samsung Plasma NOT Panel

I went to remove the F-Buffer but found the panel ribbons bonded to the buffers instead of terminating into connectors. Buggers!

I called the thread "...NOT Panel" that may have been premature. How can I probe or scope that ribbon on the address board to see if the signals are indeed there ?

[tom66]

Re: Wide Black Vertical Line Samsung Plasma NOT Panel

Huh? Those look like they terminate into connectors...? What am I missing?

[tw2005]

Re: Wide Black Vertical Line Samsung Plasma NOT Panel

I went to remove the F-Buffer but found the panel ribbons bonded to the buffers instead of terminating into connectors. Buggers!

I called the thread "...NOT Panel" that may have been premature. How can I probe or scope that ribbon on the address board to see if the signals are indeed there ?

No , that's not right, std lever action connector and ribbon

[tw2005]

Re: Wide Black Vertical Line Samsung Plasma NOT Panel

whatever you do, don't run the tv without the metal strip heatsink across those ribbons.

[mmartell]

Re: Wide Black Vertical Line Samsung Plasma NOT Panel

Sorry I should have clarified... that is a Shopjimmy pic of the buffer I thought I had until I disassembled my tv to find NO connectors. That board was just for illustration as I think everything else is the same.