backlight fail?

[cookie]

When I have the screen on my ThinkPad T40 turned on full, it will after around 20 seconds, the screen goes black, but I can still see it, but not very good. The only way to fix it, is to push Fn + F3. That turns the screen off, and then I just move the mouse, and it turns back on. But it only happens when the screen brightness is all the way up. If I turn it down a little, it won't do it. Any ideas? I thought it might be the backlight is going bad. And also, when I turn on my ThinkPad, the screen has a red tint.

[Neil]

Yep, almost certain the ccfl (backlight) is one it's way to failing. Sometimes you can continue using it that way for months, but usually it will be completely out quickly.

[ajkula66]

Red hue is a dead giveaway for a failing backlight. Nothing else triggers that symptom.

Good luck.

[cookie]

Ok, how much would it be to replace the screen?

[goofyGAguy]

Ok, how much would it be to replace the screen?

How handy are you with a soldering iron? Do you have steady hands?

[nicotean]

Ok, how much would it be to replace the screen?

Your best option is to buy a CCFL from ebay for example : http://cgi.ebay.com/292mm-CCFL-BACKLIGH ... ltDomain_0

Then you open your thinkpad, take down the screen assembly, de-solder the old CCFL and finally solder the new one.
I did it successfully on my R50p, and at the time I wasn't very clever with a soldering iron
You just have two points to unsolder/resolder.
If you already have a soldering iron, it will cost you 12$, which is less than the whole screen.

[RealBlackStuff]

See my HOW TO...

[daeojkim]

My T42 backlight has failed and I need to replace it after the typical red hue at start up that lasted for few months.
I was looking at ebay and I see a lot of backlights for XGA screens. My T42 is SXGA+ and I was wondering if the backlight is the same for XGA and SXGA+.

Can anyone tell me if they are the same?

Thank you.

[ajkula66]

Backlights differ by screen size, not the resolution.

The same backlight can be used on 14" XGA and SXGA+ LCD.

[daeojkim]

Ajkula66,

Thanks for the super fast reply... I guess I will have to try this changing the backlight business. The T42 has served me well for many years and it is still working flawlessly. I would hate to let it go just because of a backlight.

I actually have a Samsung 20" monitor that the backlight has failed... May be I can try to fix that one as well with a backlight for 20" monitors?

JK

[daeojkim]

I have one more question if someone can answer for me please?

So browsing through ebay I found 2 types of backlight one with plugs and cable that do not require soldering seen in the link here

http://cgi.ebay.com/14-1-XGA-CCFL-BACKL ... ltDomain_0

or one without cables and requires soldering.

http://cgi.ebay.com/IBM-THINKPAD-T42-23 ... ltDomain_0

Wouldn't it be just easier to get the prewired one and do a straight swap and avoid soldering? Or am I missing something and is there a disadvantage of using a prewired backlight, such as required a lot more disassembly?

I am just being cautious since I have never done this before.

Thanks.

JK

[RealBlackStuff]

The answer is: it depends.
If you use the CCFL with harness soldered on, depending on the manufacturer and model of the LCD, you will have to disassemble more and run the risk of getting hair/dust between the LCD layers. You will also have to physically push the ends of the CCFL with the silicon sleeve into its groove/slot at either end (and maybe also press somewhere alond the middle), thus running the risk of easily breaking the CCFL. It's only 2mm thick!
Also, not every brand of LCD uses the same silicon sleeves at the end of the CCFL, making for an awkward (or no) fit of these sleeves. Unless the sleeves are specifically made to fit a particular brand (IDTech, LG-Philips, Samsung, Hitachi, Toshiba, others), I wouldn't bother with these prewired CCFLs.

Using the bare CCFL, in most LCDs you can slide out the old CCFL after unsoldering the wires (and slide in the new CCFL).
If you have a steady hand and a 20-25W soldering iron, it takes only seconds to remove the old wire.
Since the wire is in a small loop around the pin at the ends of the (old) CCFL, it is already pre-shaped, and will fit straight onto the new CCFL. Putting this back on takes maybe another 15-30 seconds. And you can re-use the old, perfectly fitting silicon sleeves. In this case, you just slide them back on, no pressure on the tube!

See here also: http://www.lcdparts.net/howto/troublesh ... CCFL1.aspx
Brows that website for more info.

[daeojkim]

RealBlackStuff,

Thanks for the info. It does make sense that why you would use the CCFL lamp and solder it instead getting the prewired lamp. I will be doing it sometime end of the month.

Thank you and wish me luck.

JK