Multicam M-1 CNC Router Retrofit with Mesa 7i76e

Hi Folks, just a few pics from my recent retrofit. The machine was purchased at auction as-is by a client of mine. It is in remarkable condition and was functional but was missing the USB to RS485 interface. The kind folks at Multicam Australia quoted me AU$1500 for their $20 interface (that would only work with their antiquated software) so I declined their offer and purchased the Mesa card for a third of the price! I really didn't have to do much to the machine, I pulled out the original main board but left the power supply board and stepper drives. I also added a 24VDC power supply and rewired some of the position switch wiring that was originally 12VDC. I suspected that the actual switches were rated for over 12V and was correct, they work better with 24VDC (12VDC and centimeters are for truck drivers and dress makers people, not engineering! ). Having no drawings for the Multicam, I just sort of winged it and wired it as I thought it would probably work (and it did... first time! . One thing I will say here about the Mesa board is that I could have done with a few simple drawings showing the actual electronics of the inputs and outputs.. npn, pnp etc. that would have saved a lot of reading (engineers shouldn't have to read!). Thankfully I did have a calibration sheet from the original machine that allowed me to type the scaling values directly into linuxcnc config and get perfect accuracy first time. I haven't touched any motor tuning parameters, it works fine on the defaults! I have Linuxcnc running on a RaspberryPi4.

Overview
 

Control Panel


Power supply and original servo drive


Mesa Card 3D Printed a mounting bracket to use the original mounting holes


24VDC Terminal Strips

Original stepper drives

Looks great. My neighbour at work has 2 of these making orthotics.

It sounds like you did not find the connection sheet here
forum.linuxcnc.org/27-driver-boards/3191...ection-sheet?start=0

If it makes you feel better is was  not written until I worked out the 7i76e the hard way...