Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems.

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
  #1   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 12
Default Replacing LCD CCFL backlight

I'm the original poster and have a problem after having replaced the old
CCFL with a new one :-(
The display lights up like it should, but displays vertical lines (from
the top of the display down towards the keyboard.
I can't remember if it came in different colors or just brighter white
than the backlit background.
I connected the computer to a TV, and it displays fine there, so the
graphic circuitry and the computer itself must be OK.

I've been extremely careful with the LCD ribbon connectors, so I don't
think that's it, but of course I can't be 100% sure about that. I have
however tried carefully poking a plastic tool on top of the ribbon
cables (the end attached to its PCB), flexing the very slightly to see
if it made any difference, but there was no difference at all. This is
when the LCD is mounted in its frame (e.g. the Samsung LCD is assembled,
while the computer's rear display panel is absent, giving me access to
the rear of the LCD, exposing its PCB etc.).
I don't know how the ribbon cables are attached to the LCD itself as I
haven't flipped it around.

I've also checked to see if the data cables (from the computer to the
display are attached properly -they both a a wide ribbon cable and a
small white Molex or whatever connector (perhaps that one is for the
CCFL inverter, I don't know).
I don't know if this makes a difference or not, but I haven't attached
the aluminum tape as I first wanted to check if everything looks OK
(dust etc.) before re-assembling it properly. Would interference
(because of the lacking shielding) cause these problems?

The computer is a Apple Mac Powerbook G4.
Any ideas anyone?
  #2   Report Post  
Posted to sci.electronics.repair
bz bz is offline
external usenet poster
 
Posts: 314
Default Replacing LCD CCFL backlight

NoSp wrote in :

I'm the original poster and have a problem after having replaced the old
CCFL with a new one :-(
The display lights up like it should, but displays vertical lines (from
the top of the display down towards the keyboard.


It is likely that some of the connections along the top [or bottom] of the
LCD have been disrupted.

Likely you need a complete new screen.

I can't remember if it came in different colors or just brighter white
than the backlit background.

.....
I've also checked to see if the data cables (from the computer to the
display are attached properly -they both a a wide ribbon cable and a
small white Molex or whatever connector (perhaps that one is for the
CCFL inverter, I don't know).
I don't know if this makes a difference or not, but I haven't attached
the aluminum tape as I first wanted to check if everything looks OK
(dust etc.) before re-assembling it properly. Would interference
(because of the lacking shielding) cause these problems?


Possible but not likely. You will know when you put on the tape.
Let us know if that fixes it.


The computer is a Apple Mac Powerbook G4.
Any ideas anyone?


Look for a junker with a good screen.




--
bz 73 de N5BZ k

please pardon my infinite ignorance, the set-of-things-I-do-not-know is an
infinite set.

remove ch100-5 to avoid spam trap
  #3   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 12
Default Replacing LCD CCFL backlight

bz wrote:
NoSp wrote in :

I'm the original poster and have a problem after having replaced the old
CCFL with a new one :-(
The display lights up like it should, but displays vertical lines (from
the top of the display down towards the keyboard.


It is likely that some of the connections along the top [or bottom] of the
LCD have been disrupted.

Likely you need a complete new screen.


Bad news :-(
And this after taking the utmost care in handling the LCD. It's apparent
that Samsung don't want people replacing their CCFLs, but buy a
completely new screen instead.


I don't know if this makes a difference or not, but I haven't attached
the aluminum tape as I first wanted to check if everything looks OK
(dust etc.) before re-assembling it properly. Would interference
(because of the lacking shielding) cause these problems?


Possible but not likely. You will know when you put on the tape.
Let us know if that fixes it.


I've tried that now, but it didn't help.
I have however made some progress as wiggling the screen around gives a
very distorted, but correct desktop picture.
It flickers, and is "stretched" in the vertical direction -sort of like
a low resolution 80s computer using a TV.

So it does seem like a contact problem, but the question is where.
There's no positive sign that it is the ribbon connectors on the LCD as
I've carefully poked them to see, but then again that's from the top of
the screen (where the circuit board is placed), and the connections to
the LCD panel are further down.
Perhaps if I carefully removed the "frame" with all the layers
(reflector etc.) leaving me only with the LCD panel itself, I could
connect it to the computer internal display cable and see if it makes a
difference.
I would be able to see something on the screen with a light shining
through, even though the layers of reflectors etc. and the backlight
would be missing, wouldn't I?

Regarding the connections to the LCD panel itself. They seem to be
"sandwiched" in between glass, and look quite firm to me. I assume
they're fastened with epoxy or something around where they go inside the
LCD panel as opposed to just being loose?

Another thing: there are 3 thin "flexible PCBs" so to speak along the
left hand side of the LCD panel (viewing the LCD from the display side).
They don't see to contain any components, and extend further beyond the
width of the metal frame which surrounds the display. Are these
grounding planes or something?


The computer is a Apple Mac Powerbook G4.
Any ideas anyone?


Look for a junker with a good screen.


Yeah, I've already put out ads.
In case someone here is reading: it's a 15.2" screen (1440x960 pixels).
The particular model in my computer is a Samsung LTN152W6-L01, but for
all I know computer manufacturers like Apple might be using different
brands/models within the same resolution.
  #4   Report Post  
Posted to sci.electronics.repair
JW JW is offline
external usenet poster
 
Posts: 519
Default Replacing LCD CCFL backlight

On Thu, 05 Jun 2008 11:43:17 +0200 NoSp wrote in Message
id: :

In case someone here is reading: it's a 15.2" screen (1440x960 pixels).
The particular model in my computer is a Samsung LTN152W6-L01, but for
all I know computer manufacturers like Apple might be using different
brands/models within the same resolution.


Using google I found a number of hits for companies selling this panel.
The cheapest in the hits I looked at, is this one:
http://www.sparepartswarehouse.com/O...N152W6L01.aspx
  #5   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 12
Default Replacing LCD CCFL backlight

JW wrote:
On Thu, 05 Jun 2008 11:43:17 +0200 NoSp wrote in Message
id: :

In case someone here is reading: it's a 15.2" screen (1440x960 pixels).
The particular model in my computer is a Samsung LTN152W6-L01,


Using google I found a number of hits for companies selling this panel.
The cheapest in the hits I looked at, is this one:
http://www.sparepartswarehouse.com/O...N152W6L01.aspx


Thanks.
I also found out that Moniserv/LCDparts does LCD repairs
(http://www.moniserv.com/doc/pricelist.html) which might be worth
looking into, once I figure out where the problem lies.

It seems like some sort of contact problem as wiggling the display
around changes it from showing just a bunch of vertical lines and the
actual computer desktop (although quite distorted).
Apart from the LCD display itself it could be the connector/cable that
goes from the computer to the LCD panel.

So what I've done now is very carefully remove the LCD panel itself (the
glass only), connected the cable from the computer and having a light
from behind so I can see what's going on.
So far I only get the vertical lines, and there's absolutely no changing
in that no matter what I do.
(the reason I took the LCD panel out of its frame/assembly is because I
wanted to access the areas where the ribbon cables enter the LCD panel,
so as to carefully wiggle them to see if it made any difference -it
doesn't!). That's probably good news because it probably means that the
ribbon cables aren't damaged, but why is there no desktop display no
matter what I do? At least, when I had the LCD assembled I could wiggle
it until I saw the desktop on the screen.

This brings me to my next question...
There are 3 thin, flexible PCB type things sticking out on the left hand
side of the display. Here's a photo I've taken of the topmost one (there
are two more like it):
http://img524.imageshack.us/img524/1831/lcdedgeug6.jpg

What's the purpose of these? Are they some sort of ground connections?
I'm asking because I find it strange that the display doesn't change now
that I don't have it in its frame along with the filters/reflector etc.
as it did when I had those parts available, and everything was assembled.


  #6   Report Post  
Posted to sci.electronics.repair
bz bz is offline
external usenet poster
 
Posts: 314
Default Replacing LCD CCFL backlight

NoSp wrote in :

JW wrote:
On Thu, 05 Jun 2008 11:43:17 +0200 NoSp wrote in
Message id: :

In case someone here is reading: it's a 15.2" screen (1440x960
pixels). The particular model in my computer is a Samsung
LTN152W6-L01,


Using google I found a number of hits for companies selling this panel.
The cheapest in the hits I looked at, is this one:
http://www.sparepartswarehouse.com/O...N152W6L01.aspx


Thanks.
I also found out that Moniserv/LCDparts does LCD repairs
(http://www.moniserv.com/doc/pricelist.html) which might be worth
looking into, once I figure out where the problem lies.

It seems like some sort of contact problem as wiggling the display
around changes it from showing just a bunch of vertical lines and the
actual computer desktop (although quite distorted).
Apart from the LCD display itself it could be the connector/cable that
goes from the computer to the LCD panel.

So what I've done now is very carefully remove the LCD panel itself (the
glass only), connected the cable from the computer and having a light
from behind so I can see what's going on.
So far I only get the vertical lines, and there's absolutely no changing
in that no matter what I do.
(the reason I took the LCD panel out of its frame/assembly is because I
wanted to access the areas where the ribbon cables enter the LCD panel,
so as to carefully wiggle them to see if it made any difference -it
doesn't!). That's probably good news because it probably means that the
ribbon cables aren't damaged, but why is there no desktop display no
matter what I do? At least, when I had the LCD assembled I could wiggle
it until I saw the desktop on the screen.

This brings me to my next question...
There are 3 thin, flexible PCB type things sticking out on the left hand
side of the display. Here's a photo I've taken of the topmost one (there
are two more like it):
http://img524.imageshack.us/img524/1831/lcdedgeug6.jpg

What's the purpose of these? Are they some sort of ground connections?
I'm asking because I find it strange that the display doesn't change now
that I don't have it in its frame along with the filters/reflector etc.
as it did when I had those parts available, and everything was
assembled.


http://www.teac.com.au/pages/howdoesanlcdwork

In brief, signals come in along the edges, all across the top and side of
the screen. If any of the connections are damaged, entire rows or columns
can stop responding.



--
bz 73 de N5BZ k

please pardon my infinite ignorance, the set-of-things-I-do-not-know is an
infinite set.

remove ch100-5 to avoid spam trap
Reply
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules

Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Replacing LCD CCFL backlight NoSp Electronics Repair 18 May 27th 08 11:51 AM
replace lcd monitor ccfl backlight? [email protected] Electronics Repair 3 January 14th 07 01:36 AM
CCFL Backlight Replacement Will this work? 30,000 cd/m^2 Michael Kennedy Electronics Repair 0 April 28th 06 02:46 AM
Where to find CCFL Backlight for a laptop in Montreal Max Electronics Repair 2 February 12th 05 05:16 PM
Troubleshooting a CCFL circuit! (Backlight on Compaq Presario 900) Rob Electronics Repair 3 January 30th 05 03:21 PM


All times are GMT +1. The time now is 08:41 PM.

Powered by vBulletin® Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 DIYbanter.
The comments are property of their posters.
 

About Us

"It's about DIY & home improvement"