Wow.... This is as tough as anything...
(I found a replacement for the broken servo), but now I am working on picking out replacement encoders. Its not an easy search. They either cost over $1K each or there is no information, or they don't work...
I am kinda looking at this one:
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The 8-30 power means I would have to provide a separate power supply for them since most standard control setups like to just provide 5V. That's no big deal for me. I have a number of small 12V regulated power supplies on the shelf for other applications. 512 res is greater I think than the original encoders on this machine. I think they were only 200. 512 gives a theoretical precision of about .00039. The machine manual only claims .001 with .0005 repeatability anyway so that seems ok. DL means 5V out so that's good for most controllers.
I should go measure the pitch of the ball screws just to make sure, or see if its in my manuals somewhere. I just assumed 5tpi.