Blank screen

[Rex]

Hi there,

I have a old but trusty T21, or I did until a few days ago.

Was using it last week, all fine. Turned on today, and I hear the hdd spinning but the screen is blank, black. There are no blinking lights, just the normal '"I'm On" light. No beeps on booting, sounds fine, just on display.

Any advice gratefully taken on board,

Thanks

Rex

[RealBlackStuff]

Screens from other T20/T21/T22/T23 with the same resolution would fit.
If you have one, try it or borrow it.
Also, connect an external monitor, see if that goes.
If that is blank as well, consider another laptop.
T21 is too old (and too limited anyway) to waste any money on.
Try and sell it for parts.
Consider yourself lucky if you get £10.- or more.

[Rex]

I do have a T20 that has the BOD, that is why I bought the T21.

It works with an external monitor. I'm doing some work on my car and the laptop was fine; now it's inconvenient to get an external monitor to the car. More to the point, I'm not taking my 22" desktop monitor to the car!

See if I can find a cheap s/h one.

Thanks

Rex

[RealBlackStuff]

Just move the whole (presumably working) lid from the dead T20 to the T21.

[Rex]

Could try that but the T20 suffers the BOD. Presumably that is an mb issue rather than screen. What have I got to loose?

One of my longer term plans, when I find time with nothing better to do on my hands, is dismantle the T20 and attempt to reflow solder the mb by putting it in the oven. I have read plenty; in the worst case, I'll have a non-working T20, which I have already!

[rkawakami]

Symptom: Black (unlit) LCD, video okay out VGA port, otherwise system appears to be working normally

Possible problems (in order of easiest/cheapest solution): stuck lid switch; disconnected/broken LCD ribbon cable; disconnected/bad inverter; bad CCFL (backlight); blown fuse on motherboard

Stuck lid switch
- push down on the lid switch plunger a couple of times (only about 2 or 3 mm) to see if it feels stuck

Disconnected/broken LCD ribbon cable
- re-seat the LCD ribbon cable connected to the motherboard
- inspect ribbon cable for tears/broken traces

Disconnected/bad inverter
- re-seat the inverter board (behind lower-center of LCD bezel)
- try known good inverter

Bad CCFL
- replace entire lid assembly; besides trying another LCD panel (with CCFL inside), this also replaces the ribbon cable and inverter

Blown fuse
- check fuses near LCD connector on motherboard; believe F1, F4 and F5 are the ones protecting the power supplies going to the lid assembly

[Rex]

Thanks for all that information. Will look into it when I get a bit of spare time.

Rex

[Rex]

Just a head-up. Years ago, I had a T20 that suffered the BOD. Have been intending to see if I can fix it by some DIY re-flow soldering.

Anyway, exchanged the screens for the T21 that this thread was regarding and we are back in business. All up and running again.

Thanks for the suggestions.

Rex

[rkawakami]

Thanks for the update. As for the BOD T20, I'd say that a reflow may not be the answer: http://www.thinkpads.com/forum/viewtopi ... =3&t=94160

That was for an X31 power problem but it could very well be the same issue for the T2x BOD. If there's enough noise on the power supply (due to failing or marginal capacitors), the MAX1632 could be shutting down before everything gets going.

[Rex]

Thanks for the update. As for the BOD T20, I'd say that a reflow may not be the answer: http://www.thinkpads.com/forum/viewtopi ... =3&t=94160

That was for an X31 power problem but it could very well be the same issue for the T2x BOD. If there's enough noise on the power supply (due to failing or marginal capacitors), the MAX1632 could be shutting down before everything gets going.

Interesting link if I actually understood the language! Years ago, when the T20/21/22/23 were readily available and the BOD was rearing it's head, I followed many of the thread s on this forum. All the electronic data, using scopes, MAX1632, etc; way over my head.

But cooking the mb in case it is a dodgy solder joint, now that I understand. But dismantling/reassembling the machine is another issue. I'm sure that I will have a variety of screws left over!

Rex

[Rex]

Unfortunately, my euphoria over my T22 running again having exchanged the screen with the one from my T20 (BOD) is short lived. It was working just fine, I have had it out and about, no worries.

But today, the screen is blank again. The computer starts and powers an external monitor, but the screen, just plain black.

Have had the keyboard off and reseated the screen plug/socket but no luck.

Any ideas gratefully taken on board and tried out.

Thanks

Rex

[JBUK]

As you have swapped over the LCD it may well be the flat cable as these can go open circuit and do it intermittently too.

BTW I have spare unused T20s if you are interested.

[Neil]

Plus, all the screens for the T2x series are getting really old these days. so it well could be that the CCFL has just burned out in the second screen much like the first, since it worked fine for a little while.

[Rex]

Thanks for the various replies.

Just to give a head-up, my euphoria has returned! I tried a couple of other spare screens that I have and although they had all been working previously, surprisingly, none of them now worked.

Then I found the culprit; a stuck lid switch. When initially dismantling, the plastic had broken and I repaired it with a bit a epoxy resin, reinforced with a micro square of newspaper. That small increase in thickness was sufficient to jam the switch in the off position. A bit of bending an all appears fine now.

As it happens, just when I had repaired it, a T21 came up on my local Freecycle, so now I have a back-up.

JBUK, thanks for the offer, I think I'm OK now with two working Thinkpads. They don't get a lot of use these days.

Rex