On Thu, 01 Sep 2005 08:41:32 GMT, Mike Harrison wrote:

On Thu, 1 Sep 2005 08:38:04 +0100, Tim Mitchell wrote:

In article , Mark Carver
writes
I have a Benq 731 17 inch TFT screen, it's almost two years old. I'm
away from home at the moment but my wife told me over the phone last
night that, quote, "the screen has a dark strip two inches wide down
the right hand side"
She says that there's not a sharp line line dividing the dark patch
from the rest of image, so I've discounted any faults with the
individual pixel elements (?).

Doing some Googling it seems that TFT screens have a backlight tube ? I
found this firm that do replacements,

http://www.laptopsolutions.plc.uk/lcd_backlights.htm

... but at 200 quid for a 17inch screen ! it's not worth the bother and
expence (if that's the problem anyway).

Anybody got any experience or thoughts ?

Yes, they have a backlight tube, but normally only one or two tubes with
a reflector/diffuser arrangement to do the entire screen. So when the
backlight fails you normally either lose the whole screen illumination
or half of it. But maybe your screen has more.

I have tried to replace one in a laptop, and they are tiny (2mm diameter
glass tube) and very fragile at the ends. Not to mention the problems of
dismantling the panel in the first place.
The other possibility is failure of the inverter module which generates
the high voltage to drive the tube. This is easier to replace, being
outside the LCD panel. If there's more than one driver you can test them
by swapping them around.

Larger panels can have more than 2 tubes, especially on desktop monitors where thickness is not as
limited as on a laptop. They are also probably not as thin as laptop ones.

Here are some tube sources :

http://www.lcdpart.com/doc/ccfl.html
http://www.jkllamps.com/laptop.cfm

Just found another tube supplier in Germany - very large range - I have bought from these people in
the past :
http://www.backlight4you.com/en/prod...amps/offer.htm