geekhack
geekhack Projects => Making Stuff Together! => DIY Discussions ARCHIVE => Topic started by: themadreason on Tue, 15 November 2011, 13:21:26
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I am restoring a 122 key 1st gen model M. I got some parts from unicomp to replace the switch ASM membrane with a new one from a PC/5250, so I can interface it with a windows 7 friendly microcontroller. The bolt mode is done. The keyboard has fresh springs. The new ASM USB membrane is in place.
Now I need to interface my membrane finger tab with my microcontroller. My plan is to get the bottom half of a keyboard shell from Unicomp, cut out the press fit connector, and glue it into the old Model M shell.
Is the press fit connector a single piece with the keyboard, or can I buy it separately? I need to know how to ask Jim Ownes for this part.
"Damnnit Jim, I am a comp sci major, not an electronics repairman!"
Can I get the press fit connector separately, or is it one big lump of plastic with the bottom half of a Unicomp shell?
Some pics would be awesome, so I can think about fabricating my own connector.
I also have the old microcontroller, mainframe terminal plug, and membranes if anyone wants them. Whoever calls dibbs and pays me postage can have them. I have no idea if they work or not. I had no way to plug in the "RJ45" connector to test it out before I tore the old keyboard down. The old PCB looks good, but I am no expert. I scratched a membrane when I was slicing off rivets, but it is not on top of a circuit trace.
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I might be interested in the controller and cable so I can document the pinout and prevent future confusion about the compatibility of these keyboards...where are you located?
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I am in Midland, Texas. If it is for the greater good, I might even spring for shipping. Are you interested in the membranes at all?
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Mmm...not sure I'd have a use for the membrane sheets. I'll fire you off a PM.
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I will mail this early in the week after next. I am heading out to spend Thanksgiving with my family.
Some of your pics were helpful, Ripster. It looks like the press fit connector is part of the frame. I will attempt to fabricate something. I will have two E.E.s in family to consult over the holiday.
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I will mail this early in the week after next. I am heading out to spend Thanksgiving with my family.
Cool, thanks. No worries, take as long as you need.
You will however need my address for that...so I'll send another PM.
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OK. I will mail this package tomorrow. The connector cable is a bit grubby, and the plug is missing its tab, but it should serve your purposes. I hope that the controller makes it.
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Off it goes. Sold to the highest bidder for -$5. Auction is closed.
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Much appreciated!
Wish I could be more helpful with your original questions...I've never had one of the newer style ones taken apart before.
You may find it easiest to try to find a properly sized FFC (flexible flat/film connector) connector, stick it onto the 'fingers' from the membrane sheets, and then run wires to the controller as appropriate...may work. We must hope, of course, the matrix is the same.
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You are welcome! Those components would just gather dust and take up space here. I came up with an interface to press the finger tabs with the ASM membrane. I carved it out of wood with a hand saw, and I used zip ties to hold it all together. The interface works.
I also put a screw through a hole where there was not a corresponding one in the new ASM switch membrane during reassembly.
CRAP!
Does anyone know a good way to bridge a break in a circuit trace on a membrane sheet? I tried taping a tiny piece of copper wire over the break. This did not work. I also salvaged conductive traces off of the old ASM membrane, and I taped one over the break with electrical tape.
No success. Does anyone have bright ideas?
It may be time to talk to Jim again. New membranes are not terribly expensive, but it is more fun to solve the problem.