Andn for the record, I had 2 that were broke, but all three lights came on ...Bluemercury had that too (three lights). Might be the same cause or not. We will not know until someone who has that tries the fix.
The M2 has a bad reputation for not working. Clickykeyboards claims that 4 out of 5 M2s are broken. Bluemercury and xsphat had broken M2s too.
with the key "things" in the right state (all "away" from the sheets???)Not sure what you mean by that.
Let me clarify:Upward. If no key is pressed no switch is closed. It should work without the membrane connected. The switches are not "capacitive" but buckling spring over membrane. The membrane can be actuated without the buckling spring assembly by pressing the contact area with your finger.
With the keyboard disassembled, one cannot know what the state of the capacitive switch is supposed to be. Does key up correspond to the spring+paddle being flat against the membrane, or does key up correspond to the spring+paddle being tilted upward?
I.e., without any spring+paddles installed, will the microcontroller still go into a working state or will it go into some error state ("your keyboard is utterly destroyed, man")?It should work.
Since you replace the caps while the PCB was installed, did you test with no spring+paddle parts on the membrane??Yes.
I removed my PCB in order to inspect it better and to see if/what components there are on the other side.Maybe it's the 2.2uF. Try a tantal or electrolyte one. I did this repair with little electronics knowledge though, so maybe it doesn't matter. However, polarized capacitors won't work if loaded from the wrong side. What if the circuitry depends on that?
My 2.2uF is bipolar. My 47uF is installed right--negative toward silk label.
So--anything else I can do? Any source for the microcontroller?I don't think this is an option.
shortwave portables (Sony in particular), video cameras, whatever.
That's where I learned about the issue, Sony ICF-SW1.
Looks like it uses the same keys/buttons.
Ah, the good old original Model M. My electrolytics know they can be easily replaced so they BETTER not act up.Show Image(http://geekhack.org/attachment.php?attachmentid=2905&stc=1&d=1246151180)
My controller has two of these commonly available guys. Still surprised how long they last.
The ExplosiCaps[tm] found in PCs were a result of both faulty electrolytics with wrongly copied electrolyte and wrong derating at excessive ripple currents, i.e. the caps were deliberately run at ripple currents over spec (so one could use fewer of them) but the formulas for life expectancy calculation were off. PC mainboards are manufactured under extreme price pressure, don't forget.
Are the aluminum caps susceptible to anything similar to the electrolytic cap CAPastrophe?You mean solid electrolytic / specialty polymer? Don't think so, they can't dry out.
Well, that's what's surprising me. The first Model M's shipped in 1985 (Source: Clickeykeyboards (http://www.clickykeyboards.com/index.cfm/fa/items.main/parentcat/9523/subcatid/0/id/150921)) so we are talking 24 years.I would guess that the electrolytics present are bulk capacitance and not chosen very tightly. They could show considerable worsening of capacitance and ESR and you may not notice right away. The board might be some more finicky with long cables and stuff like that, but do you notice that unless you have another one for comparison?
I'm not worrying about it, just surprised.
When these guys start to dry out I think we'll start seeing a lot of posts like that one. Caps don't last forever.
Electrolytic ones don't, anyway. I bet the solid ones last a whole lot longer.
Wow, the "Thirst Mutilator." That's quite a claim. I could have used that for the disc golf tournament I was in this past weekend. It was HOT (over 100 deg. F). I was sick afterwards (headache, nausea). I drank 3+ gallons of water between the night before and the day of the tournament to get/stay hydrated, but it didn't work.Too much water can also be bad. I read that it happens to Marathon runners sometimes. They drink all the time to avoid dehydration but when running, the body can't remove excess water from the blood very well. So with too much water in the blood they feel nausea etc., go to the first aid tent, get misdiagnosed, get an infusion with more water and that's it. Not saying this happened to you and I'm writing this from memory.
Too much water can also be bad. I read that it happens to Marathon runners sometimes. They drink all the time to avoid dehydration but when running, the body can't remove excess water from the blood very well. So with too much water in the blood they feel nausea etc., go to the first aid tent, get misdiagnosed, get an infusion with more water and that's it. Not saying this happened to you and I'm writing this from memory.
Edit: http://www.nytimes.com/2005/10/20/sports/othersports/20marathon.html
That's strange. One of my broken M2s just came back to life.
Did anyone ever confirm this fix works (other than the OP's keyboard)? JeffreyTK's obviously never did.
Great news! Glad that worked. Maybe the other guy just used the wrong cap and they can't be bipolar.
So the seller said it was working?
I repaired my M2 today. Used an electrolytic and a tantalum cap just as the OP did. Maybe two electrolytics would suffice, but I had to buy some electronics anyway, so I went for the tantalum.
The small capacitor is quite nice to desolder. Heat everything up (really cheap and nasty soldering iron here I'm afraid) and gently push it to the side. Done. The large one was a pain and I did manage to remove about 2mm of the trace on the PCB. Not as bad as it sounds, as this was still a contact pad, so no real harm done there. I probably should have heated it up even more.
I also tried letting it sit here and unplugging/replugging it after some time webwit-style, which didn't work.
So now, I can confirm two things:
1) The seller was full of ****
2) It works now, so the modification/repair seems to work. Big thanks!
-huha
New electrolytics should last too.I'd prefer some brand-name 105° types to some cheapo 85° Taiwanese caps of doubtful quality then, i.e. better a Panasonic FC than some Jamicon or so.
Some people advise against tantalum beads, citing reliability problems (generally intermittent shorts, not a nice failure mode). Tantalums may not be that fond of rapid voltage changes and moisture (http://groups.google.de/group/sci.electronics.design/browse_thread/thread/5e4e0dc3ffdfe9e6/adb3e6740ca11f09#adb3e6740ca11f09) either.
I should be getting an M2 soon (or maybe not, the seller underestimated postage and has to sort it out.)
Did you try the crushing/removing the cap trick?
Soldering looks fine to me - I'm doing some Blue Cube connector mods and the desoldering part is by far the hardest. On through hole that last bit of solder just doesn't want to come out.
Soldering looks fine to me - I'm doing some Blue Cube connector mods and the desoldering part is by far the hardest. On through hole that last bit of solder just doesn't want to come out.I'm by no means an expert, but in such cases I sometimes drop a litte bit of recycled solder onto the lead so I can put my desolder pump into a larger pool of solder. This also helps to transfer the heat of your solder iron to the lead whereas it can be hard to melt that last bit of solder.
oooo..... nice instructions for SMT removal. Looking forward to your soldering tutorial as well.
The tutorial seems to be under construction in the wiki (http://geekhack.org/showwiki.php?title=Soldering/Desoldering).
I can't do much beyond that since CTRL-ALT-DEL doesn't work which means I can't log onto Windows (Win 2000 on this machine).
You could always load up Aquakeytest or Autohotkey and look to see if scan codes are generated.
Also, posting a pic of the back label might help.
Next logical step would be to pop it open and look for corroded membranes and coke spills.
The photos unfortunately are not showing up for me here.
The 2µ2 would invite replacement by a ceramic type in any case, you should be able to find one in 0805 or 1210 size.
Note that you cannot use them in some circuits - in some ways they are too close to an ideal capacitor, and make voltage regulators oscillate.
Show Image(http://www.freeimagehosting.net/uploads/261fe9050a.jpg)
Also, I'm considering preemptively replacing the caps. Are there any possible side effects from using ceramics rated only for 10V?
Also, I'm considering preemptively replacing the caps. Are there any possible side effects from using ceramics rated only for 10V?
A word to the wise: remove the controller from the case before soldering. I soldered mine in place, and warped the membranes from the heat. Removing the controller is not that difficult.
I've bent two springs on the M2 while inserting or removing keys. Never had that problem with the Model M either.
It'll be a nice board if it ever works.
I'm not really sure about this "nice" thing, it's awfully loud and definitely feels less solid than the M. And it's a ***** to disassemble.
Hardly one can ask more
I'd like it to work too ;)
So I will try to replace the foam strip beneath the controller with something that will put a little more force on the membrane. That foam strip has been squashed in place for 20 years and it's no good anymore.
any other ideas?
This problem is ==>NOT<== caused by the rubber mat, or the 'membrane,' as it is sometimes called, and if the mat has any remote effect, it is minor.
On this keyboard there are two thin plastic printed circuit sheets that contain the key switches