Thursday, May 7, 2015

Issues with 2WASZ keys on a Model F AT (and cleaning)

     This IBM Keyboard is truly an amazing piece of art. If you get your hands on one of this you will fall in love at the first type.

     I had 6 pcs over the last 8 Months and the one presented today with the 2WASZ keys not working, I actually owned it, (it was the cleanest perfectly looking one from the batch). The guy I sold it to seems a nice guy and really fallen in love with the Model F otherwise he wouldn't put so much effort in fixing it. He posted some inside pictures of the Model F and his efforts to make it work.


"I have managed to get an IBM Model F AT and I have an issue with it:
- the keys 2,W,A,S,Z do not work (connected to PS/2 with a DIN-PS/2 cable).

Do you have any ideas?

As a first idea I took it apart to clean it... maybe this would solve the issue.

Here is the Imgur album with the teardown and starting to clean it.

As a curiosity, it has flippers with 2 shapes. They are randomly placed:

Can this foam mat be reused? I wasn't falling apart, but it is not very resistant either

Can I use 2mm thick foam rubber, like the one below, to replace the Foam Mat? If not, where can I find some Foam Mat?

I checked the strip continuity (hopping that this may be the issue with the 2WASZ keys). none of the strip wires are interrupted:

While Cleaning the PCB with Isopropyl Alcohol, I found 2 scratches:


I checked the continuity on the both sides of the scratch and everything is ok.

In case the cleaning does not have any effect on the 2WASZ keys, do you have any ideas what may cause this issue?

I also checked the controller and the pins... some of them have continuity, some do not, but I hardly know what I am doing so everything may be ok with the Controller and pins on the ICderzemel

DanielT really was not joking when he told me that these things were build like Lego: everything snaps in place )

This topic really helped: workshop-f7/bm-at-quasi-restoration-lot-of-pictures-t9488.html

Sadly, the 2WASZ keys still don't work. I'll try an active converter, as several of you have suggested.

Until then, more images:

The metal plate, cleaned with Contact Spray (to remove a few small rust spots) and then rinsed with rubbing alcohol:

Isopropyl alcohol and a mild brush, for those hard to reach places:

Barrel cleaning:

and done:

and Flippers now:

Cleaning the barrels and flippers took wayyy to long.

And putting it back together(yes, I improvised a support). The spacebar wire was a real pain to attach :

I really struggled to remove the case screws with a flat head screwdriver, but then I realized something and I felt really stupid: the screwdriver's heads are the exact same hexagonal size as all the screws in the keyboard

And my trusty assistant, with the cleaning set-up:


In case the cleaning does not have any effect on the 2WASZ keys, do you have any ideas what may cause this issue?

If you have any ideeas please post on this blog as well. Thank you in advance,

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