Help diagnosing a non-working T40 ..

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wearetheborg · #1 Post by **wearetheborg** » Tue Jul 24, 2007 12:02 am

I got my hands on a non-working T40.
I put in a working HDD, the laptop would boot up to the boot menu, then immediately automatic reboot. Sometimes I would get a windows BSOD, and immediate reboot.
Also it seemed to me when the laptop turned on, the screen would be red.

I then booting of a cdrom, it booted off, then after a couple of minutes I think the screen turned really really faint. So faint I could not make out anything.

Now, when I turn it on, the screen stays black.. No sign of HDD booting.

Any idea what might be wrong ?

Temetka · #2 Post by **Temetka** » Tue Jul 24, 2007 1:21 am

You have a failing backlight or inverter.

Try booting then switching to external video by hitting fn + F7 to toggle the video out.

As far as BSOD's are concerned, I would reload XP on the drive. If the drive was pulled from another laptop then the XP install may fail at some low level service initialization.

I would solve the LCD issue first though.

wearetheborg · #3 Post by **wearetheborg** » Tue Jul 24, 2007 1:35 am

Temetka wrote:You have a failing backlight or inverter.

Try booting then switching to external video by hitting fn + F7 to toggle the video out.

As far as BSOD's are concerned, I would reload XP on the drive. If the drive was pulled from another laptop then the XP install may fail at some low level service initialization.

I would solve the LCD issue first though.

Thanks

I dont have an external monitor right now. Hitting Fn+F7 did not do anything.

Indeed, the drive was pulled from another laptop
I do have a debian install CD, and I CAN boot off that, but after a second, the screen again goes very very very dim, I cant see anything (except the faint debian logo, and the fact that there are menus)

Only time the screen is not dim is for a couple of seconds right after I press the power on button.

Sooo any fix for the broken backlight/inverter ?

wearetheborg · #4 Post by **wearetheborg** » Tue Jul 24, 2007 3:33 am

OK, I read
http://www.pluralsight.com/blogs/aaron/ ... aspx#48070
And my symptoms were errily similar. Red tint, then screen going black.
Turning down the brightness all the way down did enable me to install debian, I'm running it right now.
The problem is, even at the lowest brightness level, the screen sometimes goes black, and I have to shut the lid and open it again.

I assume it can only get worse ?

#5 Post by **Harryc** » Tue Jul 24, 2007 5:42 am

Yes , replace your entire LCD panel/lid assembly. You can find them on EBay or elsewhere. Make sure that you get the right part number.

Chris001 · #6 Post by **Chris001** » Tue Jul 24, 2007 7:39 am

wearetheborg wrote: Red tint, then screen going black.

LCD backlight is going bad. You need to replace the LCD panel or if you feel handy with tools, you can replace the backlight bulb itself.

Chris

Temetka · #7 Post by **Temetka** » Tue Jul 24, 2007 1:06 pm

If you are real handy with electronics you can pick up a new CCFL bulb and replace the one that is failing in your current LCD. Otherwise you might be able to sell the old LCD for a few bucks to help lessen the impact of picking up a new screen.

#8 Post by **GomJabbar** » Tue Jul 24, 2007 5:57 pm

You can replace the CCFL backlight yourself. Yeah, been there, done that.

On a 14.1" T42, the CCFL backlight is a glass tube about 11" long and about the diameter of the lead in a #2 pencil. Not the easiest thing to handle without breaking. You have to solder a small diameter wire to a pin on each end. I broke this wire a couple of times while I was trying to get everything together. The instructions say not to solder closer than 2mm to the glass tube, but there is no room in the display panel if you do it this way. You have to solder the wire as close to the glass as you can get it. You also should trim the pins sticking out of the glass tube, so that the tube will fit back into the display. There are (2) silicone insulators that you have to slide over the solder joint when you are done. Then you have to put the tube and wire assembly back into the display panel without breaking the tube.

The CCFL tubes are only about $10, so they are cheap, but they are very hard to install in the T42 panel. I recommend getting a used display lid complete off of ebay. I just got one for about $117 including all expenses. My first attempt at CCFL backlight replacement did not go well. I don't believe I broke the tube, but the backlight never did work. I had already replaced the inverter card, so that shouldn't have been it. YMMV

wearetheborg · #9 Post by **wearetheborg** » Wed Jul 25, 2007 1:46 pm

According to the following site (see last table)
http://www.blisscomputers.net/LTN141XA- ... repair.htm

They say a new LCD wont solve the problem for dim/dark/reddish tint lcd screen ?

Aaah, I see, perhaps I need to replace the lid assemly itself

wearetheborg · #10 Post by **wearetheborg** » Wed Jul 25, 2007 1:58 pm

Would this work ?
http://cgi.ebay.com/Thinkpad-T40-Series ... 0136659832

As I only need to replace the backlight, can I take my LCD and pt it into this ?

#11 Post by **richk** » Wed Jul 25, 2007 3:09 pm

No. The backlight is inside that piece. Also, if the screen is cracked, the backlight is probably broken. Also, back to your problem in the first post, a failing backlight will cause the red tint. Rebooting means a motherboard problem, so the backlight is not the most important thing.

Temetka · #12 Post by **Temetka** » Thu Jul 26, 2007 2:59 am

I would generally agree with RichK. However I am still of the belief that a fresh isntall and reseat of RAM is all that is needed to make XP stable.

Help diagnosing a non-working T40 ..

Help diagnosing a non-working T40 ..

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