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geekhack Community => Keyboards => Topic started by: mrt88 on Sun, 06 March 2011, 15:45:24

Title: Model M Non Responsive
Post by: mrt88 on Sun, 06 March 2011, 15:45:24

Hi, a few months ago I found a 1991 IBM Model M on eBay, it worked wonderfully for a few weeks but has now stopped working, I thought it was the PS2 port on my computer so I replaced it with a USB adapter but without success.

I tried a Keyboard tester and whilst it made the lock lights activate it wouldn't register any of the keystrokes, i'm somewhat at a loss to understand whats happened to it

Title: Model M Non Responsive
Post by: keyb_gr on Sun, 06 March 2011, 16:45:31

Stuck key somewhere?

Title: Model M Non Responsive
Post by: theferenc on Sun, 06 March 2011, 16:48:06

Welcome to geekhack!

There are only a few USB adapters that work with a Model M: the Belkin (http://www.amazon.com/Belkin-USB-PS-2-Adapter/dp/B000ELSXFY/ref=sr_1_5?ie=UTF8&qid=1299451566&sr=8-5&rps=1), the blue cube, and the Dynex from Best Buy.

The one that looks identical to the Dynex and the Belkin, that is available at most office supply stores, does not work.

So, maybe try one of the other adapters.

It could be a controller that has gone bad, as well. There are replacement controller projects here in the mods section, if you're handy with electronics.

Title: Model M Non Responsive
Post by: Superfluous Parentheses on Sun, 06 March 2011, 17:01:17

May be the controller broke. If so, there are a few mods on this board that completely replace the controller (http://geekhack.org/showwiki.php?title=Island:4395) or swap it with a USB controller (http://geekhack.org/showwiki.php?title=Island:8406). AFAICT, both options will require some soldering and roughly 10 ~ 40 dollars in parts. May be someone on the classifieds section here is willing to sell you an original controller board.

Title: Model M Non Responsive
Post by: jpc on Sun, 06 March 2011, 18:56:40

Check that the removable cable is fully plugged into the keyboard?

Title: Model M Non Responsive
Post by: mrt88 on Sun, 06 March 2011, 21:06:25

I doubt it's a stuck key, I stripped down and cleaned the entire thing and tested the action on every key, they're all working

I could be the adapter, it's none of those 3 and is a no name adapter in the style of the Belkin and Dynex, given what you've said about only those 3 working that's a likely cause of the error, I know the PS/2 port on my computer is broken as none of my keyboards work off it any more, I'll look into getting one of those 3 adapters and see if that fixes the problem, if it doesn't well at least I have an adapter which will work once I fix the controller

I'm not too bad with electronics but rebuilding internals is definitely a last resort step to me lol

thank you for all your help and suggestions fingers crossed I can get it working again

Title: Model M Non Responsive
Post by: bhtooefr on Mon, 07 March 2011, 07:14:01

Just to make sure, try opening up the keyboard, removing the FFC cables from the controller, and plugging them back in (it's a bit tricky to plug them back in).

Title: Model M Non Responsive
Post by: mrt88 on Mon, 07 March 2011, 10:25:59

Yes I have been hotplugging, only recently discovered that you're not meant to do that with PS/2

I removed all cables when I stripped down the board and triple checked that the cables were re seated correctly

Title: Model M Non Responsive
Post by: mrt88 on Mon, 07 March 2011, 10:33:18

until this issue occurred I never even thought about hotplugging then extra research made me realise what I'd been doing was wrong

Title: Model M Non Responsive
Post by: mrt88 on Mon, 07 March 2011, 15:37:46

Feeling happy but rather foolish now, the problem is fixed just wish I'd thought of the alarmingly obvious solution a little sooner

After what was said about hotplugging PS/2 connections I had a thought and connected up my keyboard with the computer off, lo and behold once I started it up the problem had gone and my keyboard worked perfectly, I must be too used to USB, I'd never even thought about trying whilst the machine was off....

Title: Model M Non Responsive
Post by: keyb_gr on Mon, 07 March 2011, 18:14:41

*chuckle*

That's why making things easier can be a bad thing, people get sloppy.

Anyway, good to see the problem solved.

Title: Model M Non Responsive
Post by: mrt88 on Tue, 08 March 2011, 08:31:58

certainly not a mistake I'll be making in future that's for sure, ah well always a good learning experience