IBM Model M 1391401 24NOV87

Part No. 1391401

ID No. 3284639

Date 24NOV87

Plt No. J1

This is another post to test serviceability and functionality of the subject keyboard after repair. This keyboard was sent to me for repair of broken traces and spacebar malfunction. 

First impressions: I think this is the oldest 401 I've held. Seems pretty solid and look sin pretty good shape and color. Not much stains on the casing and wear and shine on the keycaps seems pretty consistent. I would assume it had a pretty good use back in its days. 

Upon further inspection, the left mount that holds the stabilizer wire was repaired with an epoxy then eventually broke. I also assume that when the repair failed, the stabilizer wire became unbalance and caused the right mounting to brake as well.

After few photos, the keyboard was dismantled. 

Rivets clipped. Drilled. Cleaned. I then scrapped the glue/epoxy off the stabilizer bracket.

While working on the stabilizer mounting bracket, i noticed that there was an attempt to remove Left Shift's stabilizer insert.


Anyhow, I though I'll deal with this later and see if it will affect that key's smoothness.

So, i tried to design a small C Bracket to replace this keyboard's broken pair. The size I was aiming is a 6x7x4mm bracket with a gap of 2mm. My printer's nozzle is too big, 1mm, and was rather a failure. I asked for a rotary tool's help and came up with these:

Some generous amount of glue and they seat in place. Not as fancy as I imagined it but they sure hold in place and I could not feel any difference as I use this keyboard.

Steel plate. There were several corrosions on the plate but not as much compared to those I've seem. Still needs to remove rusts and repaint though. 

Grind. Sand. Paint...

[photos goes here]

The membranes. Top membrane shows broken trace at the top.

[photo goes here]


Top plate. Boots. Protective sheet. Membranes. Steel plate. ...and a lot of bolts and nuts.

Space bar. The mounts seems to do its job. I added dry lube on the brackets and wire to make sure that the sanding made on them won't cause any issue. 

I don't feel anything off nor any restraints on the springs. All I experience is the old rattly IBM Model M Space Bar. Replacing the dry lube with something heavier helps the rattle. I will apply heavier lube/grease before I send this back to the owner though. 

Left Shift. The damage does have an effect on the button. I need to re-form the barrel and apply some lubricant to fix it. All seems well now.

Yep. All done here. Keyboards seems to be fine and is back on service.