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geekhack Community => Keyboards => Topic started by: itzzspencer on Tue, 29 March 2011, 16:18:42

Title: IBM Model M2 Shift Key doesn't work
Post by: itzzspencer on Tue, 29 March 2011, 16:18:42

sorry if im posting in the wrong place. hi i've been lurking around the site for a long time now and recently found a ibm model m2 buckling spring keyboard outside. i took the baby in and followed a m2 repair guide somewhere on this site. i followed the instructions and it was fixed due to faulty capacitors, but now i have a strange problem where my shift keys dont work at all. ive tried on a pc and a mac. both dont work and i tried aqua's key test and no response from there either. neither of the 2 shift keys work. do any of you guys know what could be the problem? thanks in advance

Spencer

Title: IBM Model M2 Shift Key doesn't work
Post by: ch_123 on Tue, 29 March 2011, 17:03:12

Dead membrane trace.

Fortunately, due to the construction of the M2, it's easy to get access to the membrane. Determine which membrane traces correlate to the Shift keys (both are usually on the same row trace IIRC) and use a multimeter to find where the failure is. Then get a silver conductive gel pen and use it to draw a new trace over the dead patch.

Title: IBM Model M2 Shift Key doesn't work
Post by: itzzspencer on Tue, 29 March 2011, 17:34:58

sorry, im pretty newbie. by membrane, do you mean the board thats all black that the springs sit on or the motherboard?

Title: IBM Model M2 Shift Key doesn't work
Post by: Findecanor on Wed, 30 March 2011, 03:54:47

The black rubber sheet covers the membrane.

Title: IBM Model M2 Shift Key doesn't work
Post by: itzzspencer on Wed, 30 March 2011, 12:10:45

okay so i just pull off the rubber sheet and look for the faulty trace?

Title: IBM Model M2 Shift Key doesn't work
Post by: theferenc on Wed, 30 March 2011, 13:54:08

Yup. Definitely easier to get at the guts of an M2 than an M, isn't it?

Title: IBM Model M2 Shift Key doesn't work
Post by: ch_123 on Wed, 30 March 2011, 14:48:55

On the other hand, the M2's membrane is more awkward to service than a standard Model M one. Whereas the Model M's one consists of three separate sheets of plastic, the M2 is basically the one sheet of plastic folded into three. Also, instead of connecting into sockets on the controller with a ribbon cable, the controller card has contacts on the underside and is pressed down onto contacts on the membrane. The controller is held in place by some very flimsy plastic latches that are hella easy to break. You've been warned.

Title: IBM Model M2 Shift Key doesn't work
Post by: itzzspencer on Wed, 30 March 2011, 15:20:23

O_O thanks ch_123, hopefully i wont destroy this one