geekhack
geekhack Community => Keyboards => Topic started by: Cyberpunk on Sat, 19 January 2013, 13:49:38
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Hi, so I'm currently typing with my Model M. Sometimes, some keys (like B, N, space bar...) won't register unless I press hard on them and after that they work fine for a while :confused:...It sucks because the keyboard is in very good condition, I took it apart for cleaning using this site http://www.preater.com/modelm/ and nothing seemed broken. I would really love to save that bad boy!
edit: It's a model 42H1295 with the PS/2 cord soldered to the PCB inside the keyboard.
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Could it be that the key(s) is stuck with some dirt or the spring is bad?
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Clean the membrane
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Clean the membrane
I would have to do the bolt mod? If yes, the only DIY I found was in the archive and missed pictures, do you have one to recommend following?
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Sandy has the quintessential guide, but forget the chisel and get a chisel-tip insert for your Xacto knife. And a soldering iron is best for making a divot to guide your drill bit.
http://wiki.geekhack.org/index.php?title=Modifications:IBM_Model_M:Nut_and_Bolt_Mod (http://wiki.geekhack.org/index.php?title=Modifications:IBM_Model_M:Nut_and_Bolt_Mod)
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Sandy has the quintessential guide, but forget the chisel and get a chisel-tip insert for your Xacto knife. And a soldering iron is best for making a divot to guide your drill bit.
http://wiki.geekhack.org/index.php?title=Modifications:IBM_Model_M:Nut_and_Bolt_Mod (http://wiki.geekhack.org/index.php?title=Modifications:IBM_Model_M:Nut_and_Bolt_Mod)
Thank you! Ordered the parts from McMaster-Carr, will keep this thread updated!
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If the membrane has a fried trace (it happens) you can fix it with one of these (or something similar)
http://www.ebay.com/itm/1x-Conductive-Silver-Writer-Conductive-Silver-ink-Pen-998-/181059135607?pt=LH_DefaultDomain_0&hash=item2a27f72877
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If I were to guess, it sounds like you have some broken rivets in that area.
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If the membrane has a fried trace (it happens) you can fix it with one of these (or something similar)
http://www.ebay.com/itm/1x-Conductive-Silver-Writer-Conductive-Silver-ink-Pen-998-/181059135607?pt=LH_DefaultDomain_0&hash=item2a27f72877
Look at the outer trace, is it fried? On the other side all the traces are fine.
(http://i.imgur.com/S50U5az.jpg)
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Ouch. Some discoloration is perfectly normal, but that looks pretty much hosed, there. Impossible to say without testing. Simple method is to take a multimeter, set it to continuity mode, and test at contact points. But it looks burnt to my eyes.
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I've had traces that "looked" like that but weren't fried, but then 'others' were. Check with multimeter.
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I tried most of them with a multimeter and they were all working.
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I tried most of them with a multimeter and they were all working.
Okay, so there's two tests to do with the multimeter. The first is continuity - that's the 'quick' test that tells you whether or not the line is completely broken. Unfortunately, continuity is not the last word. Next step would be to do resistance test - obviously on lowest available setting. Sometimes lines will pass continuity but fail resistance. Still a reasonably quick one but takes a bit more time. You'll want to start with a known good line to get your baseline.
Given the description of the problem though, I doubt there's any real problems with the matrix. (Which by the way, you can order new from Unicomp if needed.) Most likely the backplate or barrel plate has a deformation. Which bolt modding may or may not fix. One of these days I should look into the costs for a run of heavy duty backplates to solve these issues - we have a number of local stamping facilities. (And it has to be a stamped part due to the curve.)
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So I received all the parts I need to do the bolt mod, now I just want to be sure what holes needs to be drilled. Everywhere where there was a stud minus the bottom row?
(http://i.imgur.com/DWh5AGW.jpg)
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You need to do the bottom row as well, though the diameter may be different depending on what you plan to do with those.
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All right, so I drilled every holes now I'm ready to reassemble the parts but it was disassembled for weeks/months and now I don't remember what's the order for the plastic membranes. In order from the backplate: backplate, rubber mat, ?, ?, barrel plate. Gosh I feel stupid now ;P!
(http://i.imgur.com/Hg7aQcG.jpg)
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All right, so I drilled every holes now I'm ready to reassemble the parts but it was disassembled for weeks/months and now I don't remember what's the order for the plastic membranes. In order from the backplate: backplate, rubber mat, ?, ?, barrel plate. Gosh I feel stupid now ;P!
That's absolutely obvious. Membrane traces have to touch each other through holes, so the order is:
Steel plate.
Membrane with traces on upper side.
Membrane with holes.
Membrane with traces on bottom side.
Rubber mat.
Hammers.
Barrels.