1988 Fadal 4020 Conversion Thoughts: MESA 6i24 + 7i49 + ?
hilo90mhz wrote: I had just found that repository - I notice the most recent commit is 4 years old, does that mean there have been no updates to the firmware since then? or just not merged from some upstream Mesa source?
Not merged from upstream. You can find the latest source under "Specifications" for each card in the Mesa web site
If you keep them fairly short there appears to be little trouble.
Do you recommend using shielded 50 pin IDE cables? for connections between FPGA and daughter boards?
Also the resolver is a more accurate 3 arc minute variety it turns out. But bad news is the bearings inside resolver are totally gone.. super rough spinning. I have disassembled it and the rest of it looks okay but I would at least have to replace these bearings.
The bearings are 0.5" OD 0.125" ID and 0.109" wide which is a very unusual size. I could make spacers to adapt a standard size 0.25" OD bearing to 0.5" OD..
Again re-evaluating options
hilo90mhz wrote: I the tachometer commutator is not concentric with the shaft
But bad news is the bearings inside resolver are totally gone.
Interesting. Generally those two components would never fail, they are zero-load bearings, so I would be looking upstream for what has given them a hard time.
It's actually a bit unusual to have resolver bearings, generally the rotor is mounted directly on the motor shaft and the stator to the backplate.
If these are brushless resolvers there is nothing to worry about dismantling and reassembling. No springs to go ping or magnets to be desaturated. Bearings should be an easy fix, but the question is _why_ they failed.
At least the other two axis motors seem to have been replaced recently along with their resolvers / tach.