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TFT Backlight replacement   
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 ?

TIA

-- 
Mark
Please replace invalid and invalid with gmx and net to reply.
Date:Thu, 01 Sep 2005 08:10:44 +0100   Author:  

Re: TFT Backlight replacement   
In article , Mark Carver 
<mark.carver@invalid.invalid> 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.
-- 
Tim Mitchell
Date:Thu, 1 Sep 2005 08:38:04 +0100   Author:  

Re: TFT Backlight replacement   
On Thu, 1 Sep 2005 08:38:04 +0100, Tim Mitchell  wrote:


>In article , Mark Carver 
><mark.carver@invalid.invalid> 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
Date:Thu, 01 Sep 2005 08:41:32 GMT   Author:  

Re: TFT Backlight replacement   
"Mark Carver" <mark.carver@invalid.invalid> wrote in message
news:3nnnrlF2ehjgU1@individual.net...

> 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).


Have you read that companies terms? "Note: We will supply backlights as a
supply only with no warranty, we will not accept a return for any backlight
that is broken, or faulty, under any circumstances, or if you find out that
the backlight is not the problem "(they are extremely fragile, and easily
damaged.) If you want a warranty, send the unit in for our fixed price
repair service"

That sounds to me like they wouldn't even replace it if it was broke in
transit!! Avoid.

At a cost of 200 for a tube is it worthwhile, considering you can get a 17"
TFT from aria.co.uk for under 100 now?

http://benq.co.uk/ServiceAndSupport/downloads/downloads.cfm?product=577&type=W
Has details about BenQ warranties, If I'm reading it correct then you should
have a 3 year warranty.

Steven.
Date:Thu, 1 Sep 2005 10:03:16 +0100   Author:  

Re: TFT Backlight replacement   
"Mark Carver" <mark.carver@invalid.invalid> wrote in message 
news:3nnnrlF2ehjgU1@individual.net...

>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 ?
>
> TIA
>
> -- 
> Mark
> Please replace invalid and invalid with gmx and net to reply.


We recently purchased a stack of these 
http://www.scan.co.uk/Products/ProductInfo.asp?WebProductID=158951 for the 
office and the image fidelity (for the price) is completely 
awesome....making previous generation TFT's look lousy.

Now I have to wait for my 4 year old home 17" TFT monitor to fail so I can 
upgrade.

D
Date:Thu, 1 Sep 2005 11:02:22 +0100   Author:  

Re: TFT Backlight replacement   
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 
>><mark.carver@invalid.invalid> 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/products/lamps/offer.htm
Date:Thu, 01 Sep 2005 10:00:27 GMT   Author:  

Re: TFT Backlight replacement   
On Thu, 1 Sep 2005 11:02:22 +0100, "vortex2"
 wrote:


>We recently purchased a stack of these 
>http://www.scan.co.uk/Products/ProductInfo.asp?WebProductID=158951 for the 
>office and the image fidelity (for the price) is completely 
>awesome....making previous generation TFT's look lousy.


I know we are wandering off topic a bit here <shrug> but what
'realworld' difference is there between Analogue and Digital input to
these TFT's please?

I ensured both the new video cards (my and my daughters machines) had
DV outputs, just in case it went that way only in the future?

All the best ..

T i m
Date:Thu, 01 Sep 2005 10:46:17 GMT   Author:  

Re: TFT Backlight replacement   
"T i m"  wrote in message 
news:cmmdh19hl6req4qejpmk8j5iahbunmvnm2@4ax.com...

> On Thu, 1 Sep 2005 11:02:22 +0100, "vortex2"
>  wrote:
>
>>We recently purchased a stack of these
>>http://www.scan.co.uk/Products/ProductInfo.asp?WebProductID=158951 for the
>>office and the image fidelity (for the price) is completely
>>awesome....making previous generation TFT's look lousy.
>
> I know we are wandering off topic a bit here <shrug> but what
> 'realworld' difference is there between Analogue and Digital input to
> these TFT's please?
>
> I ensured both the new video cards (my and my daughters machines) had
> DV outputs, just in case it went that way only in the future?
>
> All the best ..
>
> T i m


These LG monitors we bought have no DVI...(none of our PC's have DVI 
anyhow)..I'm hard pressed to believe the image fidelity could be any better 
even with DVI though.

D
Date:Thu, 1 Sep 2005 12:03:59 +0100   Author:  

Re: TFT Backlight replacement   
On Thu, 01 Sep 2005 10:46:17 GMT, T i m  wrote:


>On Thu, 1 Sep 2005 11:02:22 +0100, "vortex2"
> wrote:
>
>>We recently purchased a stack of these 
>>http://www.scan.co.uk/Products/ProductInfo.asp?WebProductID=158951 for the 
>>office and the image fidelity (for the price) is completely 
>>awesome....making previous generation TFT's look lousy.
>
>I know we are wandering off topic a bit here <shrug> but what
>'realworld' difference is there between Analogue and Digital input to
>these TFT's please?
>
>I ensured both the new video cards (my and my daughters machines) had
>DV outputs, just in case it went that way only in the future?
>
>All the best ..
>
>T i m
>


On an analogue interface, the image is converted to a voltage, then converted back to digital in the
monitor, which will inevitably increase noise. 
Probably a more important issue however is that the monitor needs to re-generate an accurate and
stable pixel clock timing signal from the analogue sync signal - if it doesn't get this quite right,
resolution and sharpness will deteriorate rapidly as the LCD pixels will not 'line up' with the
generated image. 
I must say that as an electronics engineer, I'm rather impressed at how well the monitors I've seen
manage to do this, but it can never be as good as a digital link, and will sometimes be a lot worse.
I would certainly not want to use anything above 1024x768 on an analogue interface.
Date:Thu, 01 Sep 2005 11:10:18 GMT   Author:  

Re: TFT Backlight replacement   
In article , Mike Harrison 
 writes

>On Thu, 01 Sep 2005 10:46:17 GMT, T i m  wrote:
>
>>On Thu, 1 Sep 2005 11:02:22 +0100, "vortex2"
>> wrote:
>>
>>>We recently purchased a stack of these
>>>http://www.scan.co.uk/Products/ProductInfo.asp?WebProductID=158951 for the
>>>office and the image fidelity (for the price) is completely
>>>awesome....making previous generation TFT's look lousy.
>>
>>I know we are wandering off topic a bit here <shrug> but what
>>'realworld' difference is there between Analogue and Digital input to
>>these TFT's please?
>>
>>I ensured both the new video cards (my and my daughters machines) had
>>DV outputs, just in case it went that way only in the future?
>>
>>All the best ..
>>
>>T i m
>>
>
>On an analogue interface, the image is converted to a voltage, then 
>converted back to digital in the
>monitor, which will inevitably increase noise.
>Probably a more important issue however is that the monitor needs to 
>re-generate an accurate and
>stable pixel clock timing signal from the analogue sync signal - if it 
>doesn't get this quite right,
>resolution and sharpness will deteriorate rapidly as the LCD pixels 
>will not 'line up' with the
>generated image.
>I must say that as an electronics engineer, I'm rather impressed at how 
>well the monitors I've seen
>manage to do this, but it can never be as good as a digital link, and 
>will sometimes be a lot worse.
>I would certainly not want to use anything above 1024x768 on an 
>analogue interface.


Mine is 1280x1024 on an analogue VGA interface and it is fine. However 
it seems to depend on the graphics card, another PC here blurs the 
pixels when some graphics operations occur (presumably due to the video 
timing changing slightly).

With DVI you are always sure of the pixels in the video being perfectly 
lined up with the physical pixels on the LCD panel.
-- 
Tim Mitchell
Date:Thu, 1 Sep 2005 12:19:32 +0100   Author:  

Re: TFT Backlight replacement   
Steven Campbell wrote:

> "Mark Carver" <mark.carver@invalid.invalid> wrote in message
> news:3nnnrlF2ehjgU1@individual.net...

> Have you read that companies terms? "Note: We will supply backlights as a
> supply only with no warranty, we will not accept a return for any backlight
> that is broken, or faulty, under any circumstances, or if you find out that
> the backlight is not the problem "(they are extremely fragile, and easily
> damaged.) If you want a warranty, send the unit in for our fixed price
> repair service"
>
> That sounds to me like they wouldn't even replace it if it was broke in
> transit!! Avoid.
>
> At a cost of £200 for a tube is it worthwhile, considering you can get a 17"
> TFT from aria.co.uk for under £100 now?

Indeed

> http://benq.co.uk/ServiceAndSupport/downloads/downloads.cfm?product=577&type=W
> Has details about BenQ warranties, If I'm reading it correct then you should
> have a 3 year warranty.


Thanks for that, I'll pursue that avenue when I return home. I should
still have the receipt, (I bought the monitor in a Tiny store !) but if
not it seems from Benq's T that they can still accept claims based
upon the manufacturing date. If all else fails that LG model mentioned
by Vortex2 looks tempting !

Thanks again to all for you responces
Date:1 Sep 2005 04:34:23 -0700   Author:  

Re: TFT Backlight replacement   
On 1 Sep,  
     "vortex2"  wrote:



> These LG monitors we bought have no DVI...(none of our PC's have DVI 
> anyhow)..I'm hard pressed to believe the image fidelity could be any better
> even with DVI though.



I can compare both inputs on mine. (a Dell TFT) I can't see any difference.
-- 
  B Thumbs
  Change lycos to yahoo to reply
Date:Thu, 01 Sep 2005 12:39:08 +0100   Author:  

Re: TFT Backlight replacement   
Tim Mitchell  wrote:

> >
> >On an analogue interface, the image is converted to a voltage, then 
> >converted back to digital in the
> >monitor, which will inevitably increase noise.
> >Probably a more important issue however is that the monitor needs to 
> >re-generate an accurate and
> >stable pixel clock timing signal from the analogue sync signal - if it 
> >doesn't get this quite right,
> >resolution and sharpness will deteriorate rapidly as the LCD pixels 
> >will not 'line up' with the
> >generated image.
> >I must say that as an electronics engineer, I'm rather impressed at how 
> >well the monitors I've seen
> >manage to do this, but it can never be as good as a digital link, and 
> >will sometimes be a lot worse.
> >I would certainly not want to use anything above 1024x768 on an 
> >analogue interface.
> 
> Mine is 1280x1024 on an analogue VGA interface and it is fine. However 
> it seems to depend on the graphics card, another PC here blurs the 
> pixels when some graphics operations occur (presumably due to the video 
> timing changing slightly).
> 

I've been running 1600x1200 on analog for some years now, it's fine.
I used to have an LG Flatron CRT screen which I have just upgraded to
a Dell 2001FP which is really excellent.  It has DVI and analog
inputs.  I recently ran it from another computer which happens to have
a DVI output and, to be quite honest, I didn't see any immediate
difference.


> With DVI you are always sure of the pixels in the video being perfectly 
> lined up with the physical pixels on the LCD panel.


-- 
Chris Green
Date:1 Sep 2005 12:00:44 GMT   Author:  

Re: TFT Backlight replacement   
In article , 
news@spaced.me.uk says...

> On Thu, 1 Sep 2005 11:02:22 +0100, "vortex2"
>  wrote:
> 
> >We recently purchased a stack of these 
> >http://www.scan.co.uk/Products/ProductInfo.asp?WebProductID=158951 for the 
> >office and the image fidelity (for the price) is completely 
> >awesome....making previous generation TFT's look lousy.
> 
> I know we are wandering off topic a bit here <shrug> but what
> 'realworld' difference is there between Analogue and Digital input to
> these TFT's please?
> 

My guess is that it will eventually make kit cheaper because fewer 
components are required with digital, but until it's the standard 
connection I don't think it will make much difference.
Date:Thu, 1 Sep 2005 13:10:12 +0100   Author:  

Re: TFT Backlight replacement   
On Thu, 1 Sep 2005 12:03:59 +0100, "vortex2"
 wrote:


>
>"T i m"  wrote in message 
>news:cmmdh19hl6req4qejpmk8j5iahbunmvnm2@4ax.com...
>> On Thu, 1 Sep 2005 11:02:22 +0100, "vortex2"
>>  wrote:
>>
>>>We recently purchased a stack of these
>>>http://www.scan.co.uk/Products/ProductInfo.asp?WebProductID=158951 for the
>>>office and the image fidelity (for the price) is completely
>>>awesome....making previous generation TFT's look lousy.
>>
>> I know we are wandering off topic a bit here <shrug> but what
>> 'realworld' difference is there between Analogue and Digital input to
>> these TFT's please?
>>
>> I ensured both the new video cards (my and my daughters machines) had
>> DV outputs, just in case it went that way only in the future?
>>
>> All the best ..
>>
>> T i m
>
>These LG monitors we bought have no DVI...(none of our PC's have DVI 
>anyhow)..I'm hard pressed to believe the image fidelity could be any better 
>even with DVI though.
>
>D
>
>

It's substantially better at higher resolutions because the
interfacing is done entirely digitally and not through digital to
analogue and back again.



-- 

..andy

To email, substitute .nospam with .gl
Date:Thu, 01 Sep 2005 13:28:21 +0100   Author:  

Re: TFT Backlight replacement   
In article , T i m
 writes


>I know we are wandering off topic a bit here <shrug> but what
>'realworld' difference is there between Analogue and Digital input to
>these TFT's please?


If you want to have the pc a long way from the monitor it should make for a
better quality picture and cheaper cabling. Having your pcs in a (well
ventilated) cupboard somewhere could save you a bit of space & keep the
noise down, useful for anti-theft too.
-- 
fred
Date:Thu, 01 Sep 2005 12:37:20 GMT   Author:  

Re: TFT Backlight replacement   
Mark Carver wrote:


> Anybody got any experience or thoughts ?


Benq do a three year swap out warrenty on flat panel monitors. So give 
em a call and they will send you a new one! ;-)

-- 
Cheers,

John.

/=================================================================\
|          Internode Ltd -  http://www.internode.co.uk            |
|-----------------------------------------------------------------|
|        John Rumm - john(at)internode(dot)co(dot)uk              |
\=================================================================/
Date:Thu, 01 Sep 2005 15:51:02 +0100   Author:  

Re: TFT Backlight replacement   
T i m wrote:

> On Thu, 1 Sep 2005 11:02:22 +0100, "vortex2"
>  wrote:
> 
> 
>>We recently purchased a stack of these 
>>http://www.scan.co.uk/Products/ProductInfo.asp?WebProductID=158951 for the 
>>office and the image fidelity (for the price) is completely 
>>awesome....making previous generation TFT's look lousy.
> 
> 
> I know we are wandering off topic a bit here <shrug> but what
> 'realworld' difference is there between Analogue and Digital input to
> these TFT's please?
> 
> I ensured both the new video cards (my and my daughters machines) had
> DV outputs, just in case it went that way only in the future?


A friend has a Dell 1920x1440 large widescreen display (like the large 
Apple Cinema displays) which has DVI and VGA inputs.  He uses it with a 
  Mac with DVI and a PC/laptop with VGA.  He says there's a remarkable 
difference between the DVI and VGA inputs, with the VGA showing ghosting 
and blurriness which disappears when on DVI.  I suspect this is partly 
due to the resolution, but also the physical size of the display (19"+ 
widescreen I think)

I use 1600x1200 on a 19" CRT with no problems.

D
Date:Thu, 01 Sep 2005 15:52:28 +0100   Author:  

Re: TFT Backlight replacement   
"John Rumm" wrote


> Benq do a three year swap out warrenty on flat panel monitors. So give em 
> a call and they will send you a new one! ;-)
>
> -- 
> Cheers,
>
> John.
>



Are you sure that backlight replacement won't specifically be an exclusion 
of this warranty? I saw something mentioning this on a Sony TFT I just 
purchased, but perhaps it was relating to them dying through wear and tear 
and not a malfunction.

Alex
Date:Thu, 01 Sep 2005 18:23:44 GMT   Author:  

Re: TFT Backlight replacement   
Alex (YMG) wrote:


> Are you sure that backlight replacement won't specifically be an exclusion 
> of this warranty? I saw something mentioning this on a Sony TFT I just 
> purchased, but perhaps it was relating to them dying through wear and tear 
> and not a malfunction.


I don't recall any restrictions, but then again it has been quit a while 
since I last sold Benq TFTs so can't remember with absolute cetainty. No 
harm is asking either way.

-- 
Cheers,

John.

/=================================================================\
|          Internode Ltd -  http://www.internode.co.uk            |
|-----------------------------------------------------------------|
|        John Rumm - john(at)internode(dot)co(dot)uk              |
\=================================================================/
Date:Thu, 01 Sep 2005 20:14:35 +0100   Author:  

Re: TFT Backlight replacement   
T i m  wrote in
news:cmmdh19hl6req4qejpmk8j5iahbunmvnm2@4ax.com: 


> On Thu, 1 Sep 2005 11:02:22 +0100, "vortex2"
>  wrote:
> 
>>We recently purchased a stack of these 
>>http://www.scan.co.uk/Products/ProductInfo.asp?WebProductID=158951 for
>>the office and the image fidelity (for the price) is completely 
>>awesome....making previous generation TFT's look lousy.
> 
> I know we are wandering off topic a bit here <shrug> but what
> 'realworld' difference is there between Analogue and Digital input to
> these TFT's please?


IMO, substantial. I notice it particularly where fine text is displayed. 
With DVI all the verticals are of consistent width and clean. With analog 
some appear wider and less distinct. Most pictures seem pretty much the 
same on both. However, my experience is with just two graphics cards and 
three (different) monitors. Other hardware could produce results that 
differ less markedly.

-- 
Rod
Date:1 Sep 2005 21:52:03 GMT   Author: