T21 screen does not light up; stays black

[gyred]

Yesterday when I booted up my T21 the screen illuminated for a split second in the lower left corner--just enough so I could see the IBM logo appearing--then went black, and stays that way. It was working perfectly fine the night before. The rest of the computer seems to be booting up normally--at least it sounds like it is. I can't see the screen to use the mouse.

I've tried rebooting half a dozen times and the screen never comes to life.

Any diagnostics I can perform in this situation? Anyone hear of a similar problem, or know of a possible fix?

[rkawakami]

Welcome to thinkpads.com!

Something like this can be due to several things. One of the easiest ways to troubleshoot this type of problem is this:

- Turn the laptop ON and then shine a bright flashlight on the screen, downward at an angle usually works best.
- Can you see a "ghost-like" image? That is to say, can you see the normal IBM boot splash screen followed by Windows but the screen is not lighting up? If so, then most likely the problems are a defective inverter board or a broken LCD backlight.
- The problem could also be due to a stuck lid switch. Located next to the right-hand side hinge, below the battery and power LEDs. Push it down a couple of times (with the laptop off) and then try starting the system

- If no "ghost" image is present and the lid switch doesn't help, with the laptop OFF, attach an external monitor to the VGA port on the back of the laptop.
- Turn the monitor ON and then turn the laptop ON.
- If you see the normal boot screen and Windows appear on the external monitor, it means that at least the laptop's motherboard is functional enough to generate a video signal and the problem is isolated (most likely) to the LCD display. Again, the problem could be the inverter or the backlight.

Before the screen went out, was there any kind of pink or red tint at turn-on? If so, that usually indicates a weak backlight. If it was a bright white prior to this problem, then I would vote for a broken inverter board (or loose connection to same).

If you want to try fixing this yourself, grab a copy of the Hardware Maintenance Manual for the T2x systems from here:

http://www-307.ibm.com/pc/support/site. ... UYM3F.html

It details the steps needed to take the entire laptop apart. If it appears to be an inverter problem (in my opinion, the most likely cause), it's a fairly simple matter to undo three screws that hold the LCD bezel in place and replace the inverter board. These boards can be found on eBay.

Let us know the results from these troubleshooting tips before throwing any money at the problem.

[gyred]

Thanks for the excellent analysis and troubleshooting! You hit the nail on the head. My screen had been showing a red tint at the bottom on bootup for a while, and had been growing progressively dimmer for the last year or so. I had learned to compensate for it, but I was always amazed at how bright our other screens were in comparison.

Using a flashlight, I can see a ghost image, ever so faint, on the dark screen. The data on my T21 is backed up, but if I could connect it to another monitor (there's a spare 17 in. CRT on the next desk) could I actually do some work using that external monitor and the T21 keyboard? I'd like to email some work files to my other computer, if possible.

I do need to ask: which port is the VGA port on the back of the T21? Can I take the cable that now connects that spare CRT to its computer and connect it to my T21?

I also need to ask: if this is a backlight problem, what are my options? Anything more complex than replacing a simple component is something I probably would not want to try myself.

Thanks again for the help. It's quite outstanding, and very much appreciated.

[tfflivemb2]

The data on my T21 is backed up, but if I could connect it to another monitor (there's a spare 17 in. CRT on the next desk) could I actually do some work using that external monitor and the T21 keyboard? I'd like to email some work files to my other computer, if possible.

I do need to ask: which port is the VGA port on the back of the T21? Can I take the cable that now connects that spare CRT to its computer and connect it to my T21?

I also need to ask: if this is a backlight problem, what are my options? Anything more complex than replacing a simple component is something I probably would not want to try myself.

Thanks again for the help. It's quite outstanding, and very much appreciated.

Yes, you can attach the CRT to the blue connector on the back of the T21...it is the same port as on the back of a PC. You might have to press "FN" + "F7" on the keyboard to get the video to show on the external monitor. At this point your laptop will essentially work the same as a PC. You will still have access to your files, you will just view everything on a separate monitor.

As for backlight....I would recommend replacing the entire LCD, since the backlight is a nightmare to replace. It requires partially disassembling the LCD. I tried this on 3 different occassions and broke the bulb everytime.

[gyred]

STATUS UPDATE: A few minutes ago I booted up my T21 and used the "flashlight technique" suggested by rkawakami to make out the essential components of the screen as the laptop booted up. Using the flashlight from above I was able to see my login screen, etc. (barely) and proceeded toward my full desktop display. This was a bit eerie, actually, kind of like being with my T21 in a room in the Titanic in the depths of the murky black. Of course in the midst of this gloomy squinting Norton Antivirus asks me to re-activate NAV, and after fumbling to find my mouse pointer for the nth time I get beyond that up to my regular desktop.

At that point I remembered rkawakami's advice to check the lid switch, to see if it was sticking. I had never thought this might be the problem since I rarely close the screen on the T21, but I flicked the switch a few times and voila, the screen comes back to life!! I guess the lid switch may have had some gunk in it from somewhere.

So, I now have a screen for the time being thanks to this community, and am very grateful.

Since I don't know how much longer this screen will last (it is getting pretty dim), I will start moving files over this evening, and probably hook up that external monitor to see how that works. And I don't think I'll be shutting down the T21 any time soon.

Long term, though (beyond this weekend) I should probably get myself over to the part of this forum that deals with new T60 purchases.

Thanks again for the help. It's been invaluable. I will let you know how things work out.

[tfflivemb2]

You can still use the T21, even after the backlight goes out....unless you plan on getting rid of it, there is no reason to start panicking and moving files around.

[gyred]

My T21 is now 7 yrs old, and has worked like a champ all these years. I still have uses for it, but it must be nearing the end of its design life. What's involved in replacing the LCD if I wanted to go that route?

On a similar note: On an interim basis, if my screen does fade away again, I have a choice of connecting my T21 to an external 17 in. CRT or to an external 17 in. LCD (from a Dell workstation). Would the LCD screen be more friendly to the T21 -- less load, etc.?

Thanks again for the help.

[joester]

From the T21's end, an external monitor is an external monitor regardless of size or display type (LCD, or CRT). As long as the plugs mate, the monitor should work fine.

[rkawakami]

Good to hear that your system is (mostly) working again. The red tint indicates that the CCFL (backlight) may be nearing the end of its life. It may be that flicking the lid switch encouraged the inverter to fire up the lamp or that the switch was actually stuck off. In either case, the redness and diminished brightness means that sooner, and not later, you will end up having to replace the screen.

As tfflivemb2 says, replacing the lamp is not for the faint-of-heart. I'm planning to do two, maybe three such replacements and since I've never attempted one, I bought a $25 T23 system with a broken LCD to practice on.

As far as what's involved with a screen replacement, you have a couple of options:

- Most expensive, but the easiest to perform, is a total lid replacement. If you can buy a complete lid assembly with the screen, ribbon cable and inverter already installed, tested and guaranteed, then it's a fairly simple job to do.
- Second most expensive is to buy just the LCD panel itself and remove the old one and put in the "new". It requires more disassembly work and fooling with the ribbon cable, but it's not as expensive (usually) than the complete lid.
- Cheapest to do but the most dangerous (as you can end up destroying your panel), is the aforementioned backlight replacement.

The Hardware Maintenance Manual has all of the gory details in what it takes to remove and replace the major components, with the exception of the backlight swap (there's online sites and a thread in the 600 forum which details that operation). It may be worth some small amount of insurance if you try replacing the inverter to start with. They can be had from eBay for around $10-$20. Search for "10L1402" and you should find several. Replacing just the inverter should tell you if the problem is indeed with the backlight. If it doesn't help the redness and brightness issues, then you got a spare inverter to use later on. Or, re-sell it on eBay. If it does, you may have saved yourself $100+

[Stargate199]

I personally thing just replacing the LCD itself (not the entire lid) is easier. To replace the lid as a whole, you pretty much need to disassemble the entire machine. Replacing the LCD is quite simple. Three screws hold the bezel on, and four hold the LCD in place. Pull out the LCD, deattach the two cable (video cable on back side and the backlight cable on the bottom.) Swap and do the reverse.
To replace the lid, you need to remove the keyboard, wrist pad, and various other parts to be able to remove the lid as a whole. If you can get past that (with out breaking anything. I almost did that.) six screws come out and the lid is free.

[tfflivemb2]

I agree with Stargate199...replacing just the LCD has been an easier task for me, on the T2x series. The older 600 series is slightly different....those were easier to replace the entire top half.

[rkawakami]

True, the complete lid replacement requires more disassembly of the laptop (keyboard, hinge cover, keyboard bezel) but you avoid dealing with the thin ribbon cable and trying to extract it from the existing panel and plugging it into the new one. As it should be secured by a piece of tape behind the panel, you have to drop the panel out of the lid slightly, reach in, pull the tape, then pull the ribbon cable out from the LCD connector, then install in reverse. When I've done one, I held the front of the panel with one hand (to keep if from pulling the ribbon cable too hard) while trying to extract/insert the cable with the other. Swapping the entire lid means that no handling of the fragile LCD is required.

Additionally, if you buy the entire lid assembly from, say eBay, and the seller has guaranteed that everything works properly, then you have one easier electrical connection to install (the end of the ribbon cable that plugs into the motherboard). If for some reason it doesn't work, I would think you have more of a chance getting your money back without too much of a hassle with a complete lid assembly, than you would if you tried installing a bare panel and it ends up not working.

For someone who has never dealt with a panel replacement I thought that a whole lid assembly would be easier and safer. I said that it requires "more disassembly work" when I probably should have said it is a delicate operation and could potentially damage the panel if not done right.

[gyred]

Thanks to all for the very useful info. Doing any kind of repair/replacement of the LCD is probably beyond my skill level. Looking at the IBM repair manual via the pdf link convinced me of that. For the time being I'll use the screen as is, and also try out the external monitor option just to make sure that works as a backup in case the backlight does in fact bite the dust.

[marco1]

The computer would boot normally sometimes then just show the ghost image. Hooking it up to the external monitor and it works fine. Their has never been a redish glow though. Do you think its the backlight or inverter?

[rkawakami]

49%-49% chance it's either one of those.

The other 2% is split between these areas: the lid switch or a oroblem on the motherboard. If you fiddle with the lid switch and that does not help, then the cheapest point to start troubleshooting is replacing the inverter. If that's not it, then you need to weigh the purchase of a replacement LCD panel vs. the cost of a whole "new" system.