Recently I foolishly purchased an IBM Model M 71G4644 from ebay. I did not realize that this was not a buckling spring keyboard, but rather a rubber dome keyboard. Being upset, I decided to take it apart and realized that I could replace the domes with a pivot plate and spring because the plastic cover has the housing for where the plate should go. The entire purpose of this keyboard is to make a Space Saver Model M, but because I'm bored and have nothing to do with my summer I figure this might be kind of neat to tack on to the process of making the Tenkeyless Model M.
Now, for my question. There is a rubber membrane that, for this keyboard model(71G4644), is used instead of the plate and springs. From what I understand, based on the repairing that this guy has done:
http://sandy55.fc2web.com/keyboard/repair_model_m.html It would seem there is a similar rubber membrane for buckling spring models, but without the domes that you can see in the photo I took. Can I cut those domes off and use the same rubber membrane or should I replace it all together? Also, should I replace it, where could I find one?
***************** EDIT(As well as the suspected answer to my question.) *********************
Sorry it took the entire weekend and into Monday to get back to this. Welp.. good news and bad news. The good news is that the keyboard technically works and there is no squishy or dead keys as far as I could tell. The bad news is that in order to get a response sometimes I am required to hold the key down for a long time.
I suspect at least two things that could be potentially happening. It could either be that the bolt modification that I performed is not up to spec and causing the membrane to be off center and thus requiring me to apply excessive force to the keys. Or, it is the rubber sheet/blanket that prevents proper connection between the switch leads. In all honesty, I'm leaning more towards the rubber sheet/blanket because I feel fairly confident in my work even if it was a noob-time first attempt.
So, suspected answer to my original question:
Can I cut those domes off and use the same rubber membrane or should I replace it all together?
I do not think cutting the domes off and recycling the rubber sheet/blanket will work and I think the best course of action would probably be to replace it all together, however I am still in limbo on where to attain one. Any suggestions?
Also, if anyone was interested, here is the entire gallery of what I was doing from start to finish. Maybe in my documentation someone might see an error that could be corrected.
http://imgur.com/a/HiFRjProbably sometime today or tomorrow I will try tightening the bolts and/or removing the rubber sheet/blanket to see if that may potentially solve the problem.
***************** EDIT#2(Final result and conclusion.) *********************
I am now typing to you from my modified keyboard. Here's the image of the finished product:
Here's some further information on the rubber blanket that this entire thread is supposed to be about. I talked with Unicomp and apparently the rubber sheet in question is called a blanket. Also, a new one can be ordered through the Membrane Assembly by entering into the part number field with:
"Blanket part number 1403033"This is the blanket part number for a Buckling Spring Model M. Commenting on the blanket, this blanket is incredibly thin. It feels similar to that of a rubber glove. So to finally answer everything.
Can I reuse the rubber dome membrane? -> No, it's too thick.
Where can I get a replacement rubber sheet? -> Unicomp website under the Membrane Assembly using "Blanket part number 1403033" in the product field.
And I think that covers it. Thanks everyone for your advice and help. I hope you enjoyed the little documented experiment.