Author Topic: IBM Model M not working, defect?  (Read 3328 times)

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Offline biosmanager

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IBM Model M not working, defect?
« on: Sun, 03 April 2016, 09:41:27 »
Hey guys,

so I just disassembled, cleaned and reassembled my first IBM Model M. It was pretty dirty so I cleaned the case with soap water and the PCB with distilled water, alcohol and a Q-tip (only the parts under the keys). Some days later I reassembled it and tried the keyboard.
First I hooked up an USB/PS2 adapter I found (active I think)
Looks similar to this one: http://www.amazon.de/2-Adapter-f%C3%BCr-Aktiv-PS2-Maus--Tastatur/dp/B0027YYIFK/ref=sr_1_1?ie=UTF8&qid=1459694629&sr=8-1&keywords=ps2+usb+adapter+aktiv
When booting the 3 status lights flash for a second and after booting the Num light is on.
But the keys don't work. None of them. USB 2.0/3.0 - not working.
I also tried the native PS2 port on my mainboard (mouse/kb multi port, Asus Rampage V Extreme). Again, not working.
Only the Num light. I always rebooted between switching the cables/ports.
Then I put together an old Windows 98 computer with native PS2 ports (atleast I think they are native). Also doesn't work. I tried another mechanical keyboard with Alps switches, it worked on the Win98 machine.
Is my Model M defect? Maybe there's still a little bit of distilled water in the keyboard/switches?
Unfortunately there is no model/serial number on the case, but it's a original IBM with the SDL - PS2 cable.
Is the current too low?

I don't know what to do :D Please help ;)
« Last Edit: Sun, 03 April 2016, 09:44:39 by biosmanager »

Offline E TwentyNine

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Re: IBM Model M not working, defect?
« Reply #1 on: Sun, 03 April 2016, 17:04:37 »
Can you define what you mean when you say you "cleaned...the PCB with distilled water"?

Was the keyboard working before you cleaned it?
Daily driver: SSK or Tenkeyless IBM AT
1984 Model M Industrial Prototype ⌨ 1992 Black Oval Industrial SSK ⌨ 1982 5251 Beam Spring ⌨ 89 Key "SSK" ⌨ M13 triplets

Offline biosmanager

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Re: IBM Model M not working, defect?
« Reply #2 on: Mon, 04 April 2016, 04:15:19 »
Can you define what you mean when you say you "cleaned...the PCB with distilled water"?

Was the keyboard working before you cleaned it?

Q-Tips and paper towel with a little drop of water. No, I didn't put the whole PCB under water :D
Honestly, I don't know if it was working before. I was pretty dirty and I couldn't imagine that a IBM Model M could break ;)

Offline chyros

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Re: IBM Model M not working, defect?
« Reply #3 on: Mon, 04 April 2016, 06:18:00 »
Can you define what you mean when you say you "cleaned...the PCB with distilled water"?

Was the keyboard working before you cleaned it?

Q-Tips and paper towel with a little drop of water. No, I didn't put the whole PCB under water :D
Honestly, I don't know if it was working before. I was pretty dirty and I couldn't imagine that a IBM Model M could break ;)
The model M is built very well, but not electrically invulnerable. Water in the membranes kill it stone dead and they're very heard to repair when that happens as you have to do a bolt-mod, that's if the circuitry hasn't shorted out.
Check my keyboard video reviews:


Offline biosmanager

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Re: IBM Model M not working, defect?
« Reply #4 on: Mon, 04 April 2016, 06:42:23 »
I didn't put water in the inner part of the switch with the spring. A few switches though were pretty dirty so I cleaned them carefully with an almost dry Q-tip.
Wouldn't the LED not light up if the circuit shorted out? But it does.
« Last Edit: Mon, 04 April 2016, 06:44:56 by biosmanager »

Offline xtrafrood

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Re: IBM Model M not working, defect?
« Reply #5 on: Mon, 04 April 2016, 06:46:15 »
It is generally never a good idea to let a circuit board come in to contact with water.  :(
(sold) Chris Schammert (Christopher Schammert)

Offline E TwentyNine

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Re: IBM Model M not working, defect?
« Reply #6 on: Mon, 04 April 2016, 07:15:54 »
I didn't put water in the inner part of the switch with the spring. A few switches though were pretty dirty so I cleaned them carefully with an almost dry Q-tip.
Wouldn't the LED not light up if the circuit shorted out? But it does.

You don't always have to do a bolt mod if you get water in the membrane, they can dry out, you can displace the water with rubbing alcohol, etc.

But you're not at that point.

What you want to do next is pull the membrane connectors out of the controller board and reseat them.

If that doesn't work, pull the connectors from the controller, and get a piece of wire long enough to connect the pins from one connector to the other.  With the keyboard plugged into the computer, and either Aquakey running or notepad, start jumpering random pins.   If you get typing it's not the controller.
Daily driver: SSK or Tenkeyless IBM AT
1984 Model M Industrial Prototype ⌨ 1992 Black Oval Industrial SSK ⌨ 1982 5251 Beam Spring ⌨ 89 Key "SSK" ⌨ M13 triplets

Offline JimByr

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Re: IBM Model M not working, defect?
« Reply #7 on: Mon, 04 April 2016, 14:25:24 »
Not all PS/2 to USB adapters work equally well with IBM keyboards.

Question - This is not a M2 is it?