Thinkpad Dock 2631 self-destructs on power failure?

[Chaoticmass]

Hey guys. For starters I'll re-introduce myself. I've bought a few laptops off Thinkpads.com back when I was a kid (still got my 701C) and what brings be back today is an odd problem where I haven't found a solution anywhere else on the net. It concerns the Thinkpad Dock type 2631.

At work in a retail computer store I devised a mobile workstation, a laptop that could be bolted down to a rolling cart/table, along with a label printer and bar code scanner. The purpose of the mobile workstation was for managing inventory around the store. I built this over a period of a day. I used a Thinkpad T20 I repaired from a handful of bad T series Thinkpads, and a new 2631 Thinkpad Dock. The system works beautifully. The dock is secured to the table, and when you dock the laptop and remove the key the laptop is secure and can't be stolen by customers. For inventory and a variety of other tasks, I have a nice rolling desk so I am not bound to my office all day.

Here's the problem. One day I absentmindedly unplugged the power cord from dock to the wall. The laptop froze, but after I restarted everything seemed to be fine, except now the Dock seems to be dead, except for the ports which continue to work. The dock no longer charges the laptop, the ultra bay doesn't work, etc. I didn't immediately connect the dots, so I just replaced the dock with another one and just assumed I had one that went bad.

Later, someone else accidentally unplugged my docks power cable while I was docked. This time the same thing happened and I had another dead dock. Annoyed, I replaced the dock again, but now I am very cautious. One little accident or power failure and the dock will die. This can't be normal can it? A simple power interruption while you're using the dock and it stops working? Surely not.

One last thing I observed: There is a solenoid next to the master key switch, power button, and eject button. When you power on the laptop while connected to the dock you can hear the solenoid click after a moment. When you power off the laptop there is another click in the solenoid. Once the Dock dies due to removing the power with the laptop on, the solenoid no longer clicks. Perhaps the solenoid is somehow critical to the operation of the dock, and when power is removed at the wrong time the solenoid gets locked in the wrong position. I'm not sure of this, its only speculation.

By the way, every time the dock died due to a power interruption the laptop was on, the dock was locked and power was provided through the dock's power supply.

Anyway, I've searched for a manual for the dock, but haven't found anything on IBM.com. I found a HMM, but it only explains how to remove the cover, and how to properly torque down the screws.

I turn to you, Thinkpad Gurus, if there are any of you left who know anything about this problem.

[SMA]

Wellcome back to the forum.

I also have a 2631 dock that is defect. The symptoms are as the ones described here. It was defect when I got it, so I have never actually
seen it work and I have been wondering what might have caused it to fail. I believe I know that now. Thanks for that.

The documentation you have found seems to be the same as what I found. I do not believe that there is any other documentation available.
But never the less, it can be opened. It just takes a little more time. I have had mine opened and closed again without any real problems.

There is more than one board inside so the easiest way of isolating the problem would be to have a working unit. Then swapping the potentially
bad boards into the good unit, one by one, untill the good unit stops working.
I do not have a working 2631, so I did not do a serious repair attempt. I just got me a 2877 dock.

Just a guess here, but a possible reason for this error could be if you do not have a working/charged battery in the ThinkPad.