IBM Model F XT spacebar repair

[mkontrov]

Hi folks, very few to the world of ancient IBM keyboards here and hoping for some input. I picked up a Model F XT at Goodwill for a few bucks and am interested in getting it working. I've taken it apart and cleaned it (though I did not take apart the backplate+foam+circuit board assembly) and have a semi decent understanding of how it's put together.

The only issue with the keyboard is that the spacebar, once depressed, does not come up unless you really mash on it. I'm assuming there's something wrong with the spring but I'll have to take it fully apart to be sure I suppose. I was just wondering if anyone had a similar problem and how they were able to repair it. Is it possible to just purchase some replacement parts? It's too bad it's the spacebar because everything I've read shows that to be the most complicated (and time consuming) to fix.  Thanks very much.

[SneakyRobb]

Hi,

The spacebar in the model F is pretty annoying. There is likely nothing broken with your board. When you assemble it, the spacebar needs to be seated properly. This is pretty irritating. Basically you have to assemble the spacebar before putting the backplate on.

If you just put the spacebar on the front and then try to slide the back on, the foot will stick up and not seat properly. leading to incorrect actuation.  What you need to do is have the keyboard upside down in front of you. Take off the space bar, push through a loop of floss connected to a weight. Put in the metal flipped, have the floss around the bottom of the flipper and then held down with the weight. Then you want to put the spacebar on. THEN you slide the keyboard back together. When it is slid backtogether you need to pull one side of the floss so that you can get it all out. You will have to do this procedure over and over basically till your spacebar works right.

You can also attempt to use a flat piece of metal or scraper like the forum post. It is probably the hardest part of Fxt/Fat reassembly. After 4 to 5 attempts at doing it correctly you will understand exactly what is happening and will know how to do it from then on reliably.
Only when seated correctly should you begin to add the other keys.



you can see it in this thread
https://deskthority.net/workshop-f7/ibm-model-f-xt-83-restoration-t17231.html

https://geekhack.org/index.php?topic=77644.0