Cause of lines in TFT display?

U

Usual Suspect

Guest
<http://i44.tinypic.com/357lqb8.jpg>

Installed a new CCFL tube. Was very careful (so I thought) about R&R'ing the
tube. You see the result on power-on.

Could this be a bad cable or connection? Or does it look like a damaged
display?

Thanks.--
Al, the usual
 
Usual Suspect wrote:

http://i44.tinypic.com/357lqb8.jpg

Installed a new CCFL tube. Was very careful (so I thought) about R&R'ing the
tube. You see the result on power-on.

Could this be a bad cable or connection? Or does it look like a damaged
display?
Click to expand...
Either.

Graham
 
Either.
Click to expand...
Simplest way to confirm? Any options other than to scope each line on that
*tiny* flex pc cable?

Thanks.
--
Al, the usual
 
Usual Suspect wrote:
http://i44.tinypic.com/357lqb8.jpg

Installed a new CCFL tube. Was very careful (so I thought) about R&R'ing the
tube. You see the result on power-on.

Could this be a bad cable or connection? Or does it look like a damaged
display?
Click to expand...
Could be either. Look for the mylar cables with connectors on the short
edge of the panel & reseat them. If you've torn one of them, you're screwed.

--
W
. | ,. w , "Some people are alive only because
\|/ \|/ it is illegal to kill them." Perna condita delenda est
---^----^---------------------------------------------------------------
 
Usual Suspect wrote:
Either.

Simplest way to confirm? Any options other than to scope each line on that
*tiny* flex pc cable?
Click to expand...
Scoping it won't tell you anything useful. The fact that the lines run
the width of the screen tells you that the problem is with the
horizontal drivers, which will be on one of the short edges of the
panel. Hopefully, you've loosened one of the mylar film cable connectors
(very easy to do while working on a panel), & reseating them will fix it.

--
W
. | ,. w , "Some people are alive only because
\|/ \|/ it is illegal to kill them." Perna condita delenda est
---^----^---------------------------------------------------------------
 
Could be either. Look for the mylar cables with connectors on the short
edge of the panel & reseat them. If you've torn one of them, you're screwed.
Click to expand...
No torn cables. Reseating = no joy.
--
Al, the usual
 
I'd say it's 95%+ a defective LCD panel.

Eeyore wrote:
Usual Suspect wrote:

http://i44.tinypic.com/357lqb8.jpg

Installed a new CCFL tube. Was very careful (so I thought) about R&R'ing the
tube. You see the result on power-on.

Could this be a bad cable or connection? Or does it look like a damaged
display?

Either.

Graham
Click to expand...
 
Usual Suspect wrote:

Could be either. Look for the mylar cables with connectors on the short
edge of the panel & reseat them. If you've torn one of them, you're screwed.

No torn cables. Reseating = no joy.
Click to expand...
Just a quick question. Did you take anti-static protection measures when working
on the laptop ? The simplest way is only to wear cotton ( as I do ) and not have a
carpet containing synthetic fibres but adding a grounded ESD mat and wrist strap
is the approved way.

Graham
 
Usual Suspect wrote:
Could be either. Look for the mylar cables with connectors on the short
edge of the panel & reseat them. If you've torn one of them, you're screwed.

No torn cables. Reseating = no joy.
Click to expand...
Damn. Sounds like you've managed to zap a couple of the driver chips.
Are you 100% sure that you located all the connectors?

--
W
. | ,. w , "Some people are alive only because
\|/ \|/ it is illegal to kill them." Perna condita delenda est
---^----^---------------------------------------------------------------
 
Eeyore wrote:
Usual Suspect wrote:

Could be either. Look for the mylar cables with connectors on the short
edge of the panel & reseat them. If you've torn one of them, you're screwed.
No torn cables. Reseating = no joy.

Just a quick question. Did you take anti-static protection measures when working
on the laptop ? The simplest way is only to wear cotton ( as I do ) and not have a
carpet containing synthetic fibres but adding a grounded ESD mat and wrist strap
is the approved way.
Click to expand...
Yeah. Assuming that he found all the connectors, zapped driver chips
seem to be the likely cause.


--
W
. | ,. w , "Some people are alive only because
\|/ \|/ it is illegal to kill them." Perna condita delenda est
---^----^---------------------------------------------------------------
 
Bob Larter wrote:

Usual Suspect wrote:
Could be either. Look for the mylar cables with connectors on the short
edge of the panel & reseat them. If you've torn one of them, you're screwed.

No torn cables. Reseating = no joy.

Damn. Sounds like you've managed to zap a couple of the driver chips.
Click to expand...
And there's no telling if they're on the display or the driver chip on the mobo.
Could be either end.

Graham
 
Eeyore wrote:
Bob Larter wrote:

Usual Suspect wrote:
Could be either. Look for the mylar cables with connectors on the short
edge of the panel & reseat them. If you've torn one of them, you're screwed.
No torn cables. Reseating = no joy.
Damn. Sounds like you've managed to zap a couple of the driver chips.

And there's no telling if they're on the display or the driver chip on the mobo.
Could be either end.
Click to expand...
No, they'll be the h-driver chips on the LCD panel for sure. The
symptoms are classic.

--
W
. | ,. w , "Some people are alive only because
\|/ \|/ it is illegal to kill them." Perna condita delenda est
---^----^---------------------------------------------------------------
 
Bob Larter wrote:

Eeyore wrote:
Bob Larter wrote:
Usual Suspect wrote:

Could be either. Look for the mylar cables with connectors on the short
edge of the panel & reseat them. If you've torn one of them, you're screwed.
No torn cables. Reseating = no joy.
Damn. Sounds like you've managed to zap a couple of the driver chips.

And there's no telling if they're on the display or the driver chip on the mobo.
Could be either end.

No, they'll be the h-driver chips on the LCD panel for sure. The
symptoms are classic.
Click to expand...
Fair enough. I defer to your experience.

Graham
 
Usual Suspect wrote:
http://i44.tinypic.com/357lqb8.jpg

Installed a new CCFL tube. Was very careful (so I thought) about R&R'ing the
tube. You see the result on power-on.

Could this be a bad cable or connection? Or does it look like a damaged
display?
Click to expand...
I've just thought of another possibility: If there any chance that the
conductive rubber strips between the LCD glass & the driver chips got
displaced while you were changing the CCFL? Or that you didn't bend the
metal tabs down hard enough when you closed the panel back up?

If so, it's fiddly, but it is fixable. Given that you're otherwise going
to have to toss the panel, it might be worth a look.

--
W
. | ,. w , "Some people are alive only because
\|/ \|/ it is illegal to kill them." Perna condita delenda est
---^----^---------------------------------------------------------------
 
The most common cause of lines or bands in an LCD display is not blown
driver chips, it is failed ribbon cable connections between the board
with the driver chips going to the actual LCD glass. The bonding of the
ribbon cable to the glass itself fails.

Bob Larter wrote:
Eeyore wrote:

Bob Larter wrote:

Usual Suspect wrote:
Could be either. Look for the mylar cables with connectors on the
short
edge of the panel & reseat them. If you've torn one of them, you're
screwed.
No torn cables. Reseating = no joy.
Damn. Sounds like you've managed to zap a couple of the driver chips.

And there's no telling if they're on the display or the driver chip on
the mobo.
Could be either end.

No, they'll be the h-driver chips on the LCD panel for sure. The
symptoms are classic.
Click to expand...
 
Barry Watzman wrote:
The most common cause of lines or bands in an LCD display is not blown
driver chips, it is failed ribbon cable connections between the board
with the driver chips going to the actual LCD glass. The bonding of the
ribbon cable to the glass itself fails.
Click to expand...
It amounts to the same thing, & both are equally unfixable.


--
W
. | ,. w , "Some people are alive only because
\|/ \|/ it is illegal to kill them." Perna condita delenda est
---^----^---------------------------------------------------------------
 
On Sat, 2 May 2009 23:06:47 -0700, Usual Suspect
<reply@thegroup.net>wrote:

http://i44.tinypic.com/357lqb8.jpg

Installed a new CCFL tube. Was very careful (so I thought) about R&R'ing the
tube. You see the result on power-on.

Could this be a bad cable or connection? Or does it look like a damaged
display?

Thanks.--
Al, the usual
Click to expand...
What did it look like before the ccfl replacement?
 
Bob Larter wrote:
Barry Watzman wrote:
The most common cause of lines or bands in an LCD display is not blown
driver chips, it is failed ribbon cable connections between the board
with the driver chips going to the actual LCD glass. The bonding of the
ribbon cable to the glass itself fails.

It amounts to the same thing, & both are equally unfixable.
Click to expand...

They are routinely repaired by places that refurbish large numbers of
cell phones. They replace defective or damaged LCD, and reuse the
cable.


--
You can't have a sense of humor, if you have no sense!
 
Michael A. Terrell wrote:
Bob Larter wrote:
Barry Watzman wrote:
The most common cause of lines or bands in an LCD display is not blown
driver chips, it is failed ribbon cable connections between the board
with the driver chips going to the actual LCD glass. The bonding of the
ribbon cable to the glass itself fails.
It amounts to the same thing, & both are equally unfixable.


They are routinely repaired by places that refurbish large numbers of
cell phones. They replace defective or damaged LCD, and reuse the
cable.
Click to expand...
It's a bit different for a full size screen. ;^)

--
W
. | ,. w , "Some people are alive only because
\|/ \|/ it is illegal to kill them." Perna condita delenda est
---^----^---------------------------------------------------------------
 
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