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ThinkPad 701C top motherboard types

Older ThinkPads.. from the 600, the 7xx, the iSeries, 300, 500, the Transnote and, of course, the 701
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tdot
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Joined: Thu Jun 28, 2018 1:48 am
Location: Toronto, Canada

ThinkPad 701C top motherboard types

#1 Post by tdot » Sat Sep 08, 2018 8:11 pm

Hey there,

I finally got myself a mostly working 701C and successfully rebuilt the battery - except it has one issue. Randomly (and seemingly, often) the mouse pointer just dies. The only way to get the mouse working again is to hibernate and wake it up again. I tried using an external mouse, but it suffers from the same issue, even when turning the TrackPoint off. If anyone has any ideas for the issue ... otherwise ...

I see on eBay, there seems to be 3 different top motherboard models listed for the 701C. There seems to be:

04H8343
03M1039
41H7188

I'm thinking of purchasing one to replace the top motherboard on my 701C, to hope it solves the mouse pointer issue, but I was wondering if there are any 701C experts around that know the differences between the different part numbers.

I'm curious if some of them are a later revision with more 'fixes', which I assume I'd prefer ...

Thanks for any info,
Ryan

TheForgottenKing
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Re: ThinkPad 701C top motherboard types

#2 Post by TheForgottenKing » Mon Sep 10, 2018 10:28 pm

They appear to be the same thing. Also, I doubt that is your issue, but if it is I might have a spare board.

hwattys
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Re: ThinkPad 701C top motherboard types

#3 Post by hwattys » Wed Sep 12, 2018 10:55 am

Me, too I have several all tested working. It's the lower planars I don't have.

tdot
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Re: ThinkPad 701C top motherboard types

#4 Post by tdot » Thu Sep 13, 2018 1:39 pm

TheForgottenKing wrote:
Mon Sep 10, 2018 10:28 pm
They appear to be the same thing. Also, I doubt that is your issue, but if it is I might have a spare board.
Hmm, why do you doubt that is the issue?

As far as I can tell, the TrackPoint interface circuity and calibration circuity all seems to be on the top board, though I could be wrong.

It seems to randomly fail when it hasn't be used for x amount of time, and can be reset when sleeping/awaking the unit, so I assume there's something wrong with some part of something to do with the calibration ... which I assume is on the top board?

That's my guess, at least.

If one of you wants to sell a top board I'd be willing to buy it from one of you rather than eBay :)

TheForgottenKing
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Re: ThinkPad 701C top motherboard types

#5 Post by TheForgottenKing » Thu Sep 13, 2018 10:11 pm

I would talk to hwattys, he knows what he is doing. Could be software issues, generally hardware issues aren't fixed by a reboot.

tdot
Posts: 40
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Re: ThinkPad 701C top motherboard types

#6 Post by tdot » Sat Sep 15, 2018 2:43 am

TheForgottenKing wrote:
Thu Sep 13, 2018 10:11 pm
I would talk to hwattys, he knows what he is doing. Could be software issues, generally hardware issues aren't fixed by a reboot.
Hmm, definitely not a software issue. I was wondering that at first, but it seems to depend on the temperature of the unit, and it's not just restarting that will 'fix' it. I was going through the HMM and came across this:
Note: The TrackPoint III performs automatic
compensations to adjust the pointer sensor. During this
process, the pointer moves about the screen for a short
time. This self-acting pointer movement can occur when a
slight, steady pressure is applied to the TrackPoint III
pointer when the computer is powered on, when the
system is running, or when readjustment is required
because the temperature has changed significantly within a
short period of time or the temperature is higher than its
operating temperature. This symptom does not indicate a
hardware problem. No service actions are necessary if the
pointer movement stops in a short period of time.
However, the TrackPoint III will not stabilize if you apply
pressure to it. If pointer movement occurs, you can go into
Suspend mode, and then resume normal operation.
Resuming or turning the computer on both cause the
TrackPoint III to be calibrated, which may correct the
problem. If you see continual movement of the pointer, the
TrackPoint III is probably defective. In rare cases, the top
system board can also cause this problem.
So, I decided to 'suspend' and then 'resume' the unit, and bam it comes back. And then shortly dies again. Suspend and resume its back ... leave it alone for a few minutes, bam it's dead.

After restoring the battery I did update the BIOS to the latest, so I don't think it can be an error there. I also attempted resoldering all the components around the TrackPoint circuity on the top board in case it was just a cold solder joint, but I'm unsure what component actually performs the calibration routines (which I assume is what is actually somehow causing the failure). Didn't get better, or worse, but it's annoying.

For now at least, an external mouse works fine, if you disable the TrackPoint in the BIOS (otherwise the external mouse dies as well). But since the HMM says the top board, I'm hoping a new top board will fix it ...

Anyway, if one of you think I'm partially making sense and want to unload a top board, just PM me with a price.

Thanks,
Ryan

TheForgottenKing
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Re: ThinkPad 701C top motherboard types

#7 Post by TheForgottenKing » Mon Sep 17, 2018 4:57 pm

At the moment I need mine for my matching thinkpads but they can be found on eBay for $65 OBO, try $40

TheForgottenKing
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Re: ThinkPad 701C top motherboard types

#8 Post by TheForgottenKing » Tue Sep 25, 2018 9:21 am

My 701C just did the same thing, and has an issue turning on (the switch is not working right). Will replace top board and report back, but TPIII issue has only happened once.

tdot
Posts: 40
Joined: Thu Jun 28, 2018 1:48 am
Location: Toronto, Canada

Re: ThinkPad 701C top motherboard types

#9 Post by tdot » Thu Oct 11, 2018 1:29 am

Well, as an update, I just replaced the top board, and the TrackPoint now works perfectly! I still think it was something with the calibration circuity.

Also as an interesting note, even though both boards are marked "IBM FRU 04H8343", they are slightly different. There's probably a revision code somewhere on them, but I'm not opening it again.

The boards have (at least I noticed at a glance) some slightly different capacitor arrangements, and the 'original' board actually has a jumper wire connecting to a transistor jumpered to the board (obviously a stock job), as well as another jumper wire between a resistor and cap. The new board has neither of these. Plus, the new board has a "PRESS HERE" silkscreen where the connector to the bottom board is, while the original was lacking one.

I guess there was more than one revision of 04H8343.

Now to install the 1 gig PATA SSD I got, and learn how to install Win95 with a PCMCIA card CD drive :)

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