T21 Screen issues.

[Mevunky]

Heya all,

Well having owned many IBM's my G.F has my old T21.

It randomly wont turn on the screen at boot, this includes BIOS etc.

Leaving the machine for X (x being totally random but usually less than 10 minutes) minutes the screen will just turn on.

Could be be a loose cable? but it always turns on, e.g you leave the laptop sitting on a desk and walla working it is.

Once the screen is going it doesnt stop working untill the laptop screen has again been left off for 1-X hours.

Any help appreciated

[rkawakami]

Welcome to thinkpads.com!

This is very interesting... you have just described an identical problem that I have had with a 600E for the last two years or so. You turn the laptop on and the backlight does not light up. You can see pixel activity if you shine a bright light on the screen. Wait 5 to 10 minutes and the backlight finally decides to turn on. If I use the Fn+F7 key sequence to cycle between the LCD and external monitor, as soon as the LCD goes off, it stays off for another 5 to 10 minutes. I have checked the cable connections, the lid switch, replaced the inverter board and the entire lid (LCD panel, cable and inverter) and still have this problem. I am now assuming that there's something on the motherboard that is causing this problem. As I don't use that system anymore I haven't spent the time trying to track down the problem.

For your case, if you can spend a few dollars and some of your time, you can verify that you have (or have not) the same problem as my 600E. Replace the inverter board first as they are fairly easy to find on eBay and are relatively cheap ($10-$15). If you have the resources and inclination, swap the lid with another T2x system. You can use IBM's detailed Hardware Maintenance Manual to disassemble your T21:

T2x HMM

Good luck!

[Mevunky]

Backlight eh, id have to check but it sounds about right, ive never actually shined a torch at it or anything.

Odd that after replacing the inverter etc in your unit it hasnt helped.

She will only be using this unit for a few more months so its not really an issue as long as it keeps turning the backlight on eventually haha.

Going on what you are saying its probably not wroth screwing with all tht much, poking the cable seems to sometimes bring it on...but this might just be lucky, since it does turn on by itself how can it be the cable!

Hmmmm, wondering if its worth sourcing and inverter....maybe someone has seen this before. Yer gotta love the service manuals, rebuilt most of the T21 myself at one point.

[tselling]

This could be that the switch that the LCD depresses to turn off the backlight when you close the LCD is staying down. I found that to be the cause of a supposed backlight problem. See if you press down on the switch with the tip of a pen... how much does it depress and does it pop back? Another way to test to run without the keyboard bezel installed.

[Mevunky]

That was indeed the problem, I didn't realise that button set the LCD backlight in and out of motion.

Thanks, a lot