In search of 4B3A Microswitch Keyswitches (for a restoration, not a keyboard collector!)

I know what you guys are thinking- no, this isn't for a keyboard collection or some modern build or some other nonsense like that. I have a friend who is restoring a fairly interesting and historically significant vintage computer- a and subject to what appears to be a batch-related encapsulation failure on the proprietry hall effect sensors, but could have been some other trauma, around a little over half of them are bad. The correct SD-series replacement switch would be the 4B3A- *** These can allegedly be found on some of the Diablo printing terminals.** It is possible other switches ending in ***A could be made to work with a bit of labor and disassembly (swapping the fairly brittle sensors). I am not a keyboard expert but I have learned that you can remove a key on some of these microswitch keyboards and read the model fairly easily. Please let me know if you have a lead on a donor for these switches. They will be put to good use, and you can reply to me off list for more details. Thanks, - I