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geekhack Community => Keyboards => Topic started by: tchuladdiass on Sat, 03 March 2012, 19:36:39
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I have (or at least had) a very nice Unicomp 101-key APL keyboard. So, I managed to get water into the key switches. I either spilled a glass of water on the keyboard, or I was cleaning it under a faucet, which ever sounds less stupid (hey, it's got drainage channels, right?). A couple keys start sending out multiple codes, and some are stuck on, etc, mostly toward the bottom row (shift key, and "X" sends out both X, and a period, for example). So I pop off the key caps & stems to let it dry out. Then a couple-three days later, I plug it in, and nothing is working.
Come to find out, after opening the keyboard case (which is what I should have done first), there was water pooled up int the bottom of the keyboard, which raised the humidity level of almost all the contacts so that the controller was registering the keys as all jammed. So I try drying a bit with a hair drier, and also sit it by a heat vent for a day or so. Next day, still no work. So I pop off the controller, check with an ohm meter by the contacts, and sure enough most of the contacts still show some continuity. Leaving it apart for a few more days seems to remedy the situation a bit more, but some columns of keys still weren't working. I'm thinking major damage must have happened from the hair dryer. So I pop off the rivets (at this point I'm prepared to go forward with a bolt mod), and further check the various traces. Turns out, it seems I had managed to scratch the traces on the plastic membrane (up close by the keyboard controller) with the leads from the ohm meter. Should be easy to fix, so I pick up a conductive pen from Radio Shack (cost me 20 bucks), and start to draw over the metal traces where it appears to be scratched. But I do a sloppy job, and I end up wiping off my mess (all by the leads where the keyboard controller makes contact), and end up wiping off the bulk of the existing circuit leads. Now I have to re-draw the traces with nothing to guide me.
Long story short, I quickly pound out some Postscript code to generate the appropriate circuit pattern, print it out, tape it under the plastic membrane, and proceed to re-draw the traces (this time with a bit more sleep behind me, and a large magnifying glass). Not perfect, but it seams to do the job. The ohm meter shows that everything check out (I'm being a bit more careful this time not to scratch anything); all that's left to do is to finish the bolt mod. It will take a week or so before I get another few hours of time for this, so meanwhile I need to make sure I don't lose any of the loose pieces (the springs / hammers, and key caps).
Meanwhile, I finally get a response from a ticket I opened with Unicomp. They are willing to sell the membrane for 10 bucks (cheaper than what I paid for the circuit tracing pen). They now have the membranes up on their web site in the spare parts section (thanks to my inquiry). I'm tempted to just order it and be done with, instead of trusting my repair job. I just which I hadn't spent $20 on the circuit writer pen.
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Are you asking a question?
You made a game attempt at a creative solution, and succeeded. Congratulations!
If I had a nickel for every $20 bill I have wasted in my life, I would be in the Rip-o-meter business. The 20 you spent on the pen was the price tag for the lesson learned. A good lesson at a fair price. And you still have the pen!
A $10 sawbuck for a fresh new part is a bargain. Buy it, install it, and keep the pathetic repair job in an envelope in a drawer for that day in the future when you are desperate.
This is a good thing.
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Are you asking a question?
You made a game attempt at a creative solution, and succeeded. Congratulations!
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A $10 sawbuck for a fresh new part is a bargain. Buy it, install it, and keep the pathetic repair job in an envelope in a drawer for that day in the future when you are desperate.
This is a good thing.
I wasn't really asking a question, just venting I guess. But I've still got to decide if I want to at least attempt to re-assemble the keyboard with my repair job, including lining up all those little spring/hammers, (um, I mean, pivot-plates), and take a chance of it not working (and feeling bad about it, and have to tear apart and re-assemble it again), or to just order the replacement part and be done with (still have to drill out all those studs and line everything up either way, it's just that I might have to do it twice).
But you're right, this is a good thing. At least I won't be afraid of the bolt-mod job any more (or I will learn that I'm not dextrous enough for it, either way). If bolt-modding is easy enough, then I may order one of the 122-key keyboards from Unicomp and re-arrange things the way I see fit (horizontal Enter key for example -- I've got two different answers from them if I can order one that way).
I'd also like to order a few more pivot plates, and blank keys, so I can get a few extra keys on the keyboard. I purposely didn't get a 104-key board originally because my thumbs keep hitting the Windows key, but I could probably use an extra key or two so I can have a "compose" key, and possibly a hyper and super key. There is an extra pad under the Enter and Plus key on the keypad, and an extra pad under the left shift key.
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I feel both pity and admiration for you.
I think you made a sterling effort to repair the keyboard, and I don't think you should feel bad.
If it were me, then I would chalk it up to experience, thank my lucky stars that a replacement part was available off the shelf for a low price, and spend the delivery waiting period on completely stripping and cleaning every single little part.
I'd worry about the longevity of a repair made with a condictive pen. I'd much rather get it all cleaned up as good as new and with a brand new membrane and have an essentially brand new keyboard.
A little tip for disassembly if you choose to do it.
Disassemble it inside a large clear plastic bag, so you don't lose small parts or springs.
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Meanwhile, I finally get a response from a ticket I opened with Unicomp. They are willing to sell the membrane for 10 bucks (cheaper than what I paid for the circuit tracing pen). They now have the membranes up on their web site in the spare parts section (thanks to my inquiry). I'm tempted to just order it and be done with, instead of trusting my repair job. I just which I hadn't spent $20 on the circuit writer pen.
I saw that on their website. I think offering a replacement membrane for $10 is rather cool.
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Should be easy to fix, so I pick up a conductive pen from Radio Shack (cost me 20 bucks), and start to draw over the metal traces where it appears to be scratched.
Done that. The Silver pens that Radio Shack sells don't work on those membranes, they are for PCB circuits.
I have been looking for some kind of Carbon Graphite based ink to repair a couple of membranes and so far the best advise I have found is to make my own ink. It's in my todo's for this month. The link:
http://www.instructables.com/id/Conductive-Glue-And-Conductive-Thread-Make-an-LED/
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You want to try your mechanical skills and the spilled water is just a convenient excuse to open your keyboard. So far so good. You have learnt a lot about how things work.
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I want to see their APL keys.
Their own pics suck.
Tell you what. As soon as I get my keyboard re-assembled, I'll post pics. Their APL layout is the same as the IBM layout, however the orange seems to me to be a bit lighter in color.
One thing I'm thinking of doing is if I can find some rubber stamps of the Greek alphabet (upper/lower), I'm going to stamp those on the fronts of the keycaps in dark (forest) green. I figure a stamped key label would last long enough if it is on the fronts instead of the key top.
Later on, I may order a 122-key, and put the APL keys on that keyboard. Would require the horizontal Enter though, since one of the APL syms is on the backslash key (which is narrower on keyboards with a vertical Enter). In my online chat session with Unicomp, they said they could do a horizontal enter, but the email I got from a ticket I opened 3 weeks ago said otherwise. Don't see what the problem would be, all they have to do is move the one spring/hammer during manufacture (unless they have an inventory of 122-key units and don't want to make any more).
BTW, if I wanted Unicomp to do a custom scan code layout, would they be able to ship me an epromp chip to plug into the controller, or would I have to send the keyboard back to them?
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So here's the update. I got the keyboard back together, with the membrane that I attempted to repair. The good news -- all keys seem to work. The bad news, quite a few columns (4 - 5 columns, at least) produce more than one key code. So obviously I either have some traces run together, or the lines got a bit squiggly where they meet the keyboard controller board.
Now I can re-attempt the repair (maybe this time using a straight edge); but I think I'm going to order the replacement membrane from Unicomp.
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You can attempt to establish a company competing with Unicomp already.
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Good news... I got my replacement membrane in, installed it, screwed the keyboard back to together, and everything seems to work. So far, I've got a staggered row #4-40 3/8" rounded head machine screws / nuts going down the center axis of the keyboard, where the bulk of the pressure appears to be. Used 7 screws in all. I also left the plastic nubs on, didn't bother chopping them off. They end up holding in place for the most part. A couple spots on the bottom row was a bit loose, so I had to put some 1/4" screws (of the same type) in from the bottom side (drilled the holes small enough so that the machine screws self threaded). I know I'm going to have to put a few more in, as the keyboard now has quite a bit of ping, and a couple of spots just don't feel right. But that can all come in time -- for now I have my Model M keyboard back! And I kind of know what I'm doing now, which is a plus.
I may still end up ordering a 122-key keyboard, and using this one as a spare, until I can get it "tuned" properly (will have to play around with the proper torque on the screws, and put the rest of the screws in that I need). All in all, once I had the right parts, it wasn't such a bad job.