T21 BOD- motherboard replacement?

[Rletson]

My wife's T21 (2647-8AU/Win 2000) seems to have BOD--fan comes on, hard drive spins up, but no LCD and no response from F1. After reading around here and on the Lenovo site, I tried all the remedies (pulled components, powered-on with battery and wall juice only, etc.), and it seems well & truly comatose. Despite never having done surgery on a laptop before, I'm willing to try replacing the motherboard, but I recall reading (on the Lenovo Support 6site, I think) something about matching unit serial numbers with BIOS data. I'm also wary of getting a board with a BIOS password set. What gotchas should I be on the lookout for? I understand that almost any T2x series board should physically fit, but again I can't be sure I've found all the best-practices posts.

[rkawakami]

Welcome to thinkpads.com!

The BoD ("Blink of Death") is characterized by the following: only the hard drive LED flashing for like a 1/10 of a second when the power button is depressed. No other signs of life are seen - no hard drive spin up, no fan, no beeps, no video activity, nada. From the sounds of it, your wife's T21 does NOT have the BoD. What might have happened is that the LCD backlight is not turning on. Try hooking up an external monitor to the VGA port on the back of the system and see if there's any activity there. Best thing to try is this:

- push the power button
- when you hear the fan spinning up, immediately press the F1 key a couple of times
- watch the external monitor. If after 30 seconds or so nothing happens, then try the Fn+F7 key combination

As far as the motherboard replacement goes, I believe that you can use any T20-T22 motherboard and have it fit the base. I'm pretty sure that the T23 motherboard will not fit inside the T21 base; there's too much of a difference with the MiniPCI area between the two types of systems. About the only problem related to serial numbers is that the replacement motherboard's serial number will not match the one printed on the bottom of the system (but it can be adjusted). You would have to trust the seller that there's no BIOS password set AND that the board doesn't have the BoD. However, the problem with the BoD is that it doesn't always show itself. The motherboard could boot several dozen times before throwing the error. And then it's a matter of waiting for it to work again...

[Rletson]

Thanks for the suggestions. Tried the external monitor--no joy. The puzzling thing about the machine's behavior is that once the drive spins up there's no boot-up activity--it just runs. Nor are there any of the error-condition beeps I'd expect, though removing the memory did yield the no-memory series, so some part of its tiny BIOS brain must be functioning. So maybe there's a video-card problem? I'd like to figure out what to replace/repair so my wife can go back to working in her familiar environment (and I can get my X31 back).

If it is a motherboard issue, I noted one eBay dealer (tpads-plus) who offers to reset the serial number and upgrade the BIOS. It would be nice to know whether anyone here has dealt with this outfit (or whether there are any ThinkPad-specific gotchas, beyond the obvious ones, to watch for among parts dealers).

[nikki605]

An honest seller of quality used parts on eBay is lady_fixalot: http://myworld.ebay.com/lady_fixalot/

That's where I got my T21 motherboard in 2007 when it developed the BoD. That board is still working in my T21.

[rkawakami]

You might also want to try another PC100 low density memory module if you have access to one. There could be a problem with the one(s) you now have in the system. It's possible that the laptop can start up without throwing a memory error (1-3-3-1 beeps), yet not allow booting. Also, please confirm that you've tried removing the MiniPCI modem or combo card and attempted power up. When that card fails it can sometimes lead to no-boot condition. I'm throwing out these ideas as they don't cost any money .

[Rletson]

Thanks again. After reading up on BOD here and elsewhere, I pulled everything pullable--CD drive, internal modem, PC Card, memory, even the CMOS battery. The only change in behavior I noticed was that at first the fan wouldn't run right (it would rev up and down) and the hard drive wouldn't spin up. Then those two went back to normal, but there's no video output (internal or external) and apparently no POST. Based on some forum discussions, I begin to suspect the power-regulation components, which (IIRC) are integral to the motherboard. Or maybe something like the loose clock crystals in the 4/8/07 "Interesting fix to T23" post, or some other physical-connection/cracked-trace/cold-joint problem. I confess that my days as a patient soldering-pencil troubleshooter are long gone (not that I was ever more than a putzer-arounder), so if the quick-and-dirty (and fairly cheap) fix is to swap motherboards, that's the one I'll accept. Though I'm still open to suggestions for other approaches or possibilities.

[RealBlackStuff]

A pulsing fan points to one or both loose inductors on the bottom of your motherboard.

There are other inductors as well:
The big rectangular one near the CPU is missing on the picture, but sits at A1/A2 on
http://www.rkawakami.net/ibm_t2x/mobo_top_72_legend.jpg
The not-charging (gray square blob) is located at G6

The ones that cause a pulsing fan (gray square blob) are at D9 and E8
on http://www.rkawakami.net/ibm_t2x/mobo_b ... legend.jpg

On your own mobo, wiggle those blobs. They may well come off. When you solder them back on, there is no polarity, either way is fine.

The above pictures are of a T23, but a T20/21/22 mobo is built up similarly.

[Rletson]

Tonight I changed the memory stick from one slot to the other, got a "no memory" beep code, swapped it back and got--a bootup. So I'm quickly dumping my wife's data files onto a thumb drive and an external hard disk and getting ready to do a bit of torture testing to see whether this is a temporary recovery. Gotta love intermittent glitches.

On edit: Could this have been the same kind of memory-slot problem dealt with in a neighboring thread on T30s? Maybe a bit of antistatic foam would fix things until I feel strong enough to re-learn my soldering skills.

[SMA]

The loose memory socket problem also occurs on T20/T21/T22 ThinkPads. I have had a couple myselves.
Your symptoms does indicate that that is most likely the problem you are facing.
But first, follow Rays suggestion and try another stick of PC100 memory, if possible.

[Rletson]

Old-tech RAM isn't available locally (curse you, Best Buy!), so I'm going to accept the PC-DOC verdict that my memory stick itself is OK. The unit has been behaving properly through the process of re-installing hardware, with all the handling and flexing, so I'm going to run the tests again just to confirm, then declare victory and withdraw, at least until it misbehaves again.

Thanks to all and thanks to the board proprietors and moderators for maintaining a body of helpful information and advice. This site will stay high on my Bookmarks list.