Re: Where do I start?
That looks like a fun project, I used to have a Thermwood 4x8 that I did a complete retrofit on. The good news is that the Thermwood is built like a tank, good bones if it is mechanically OK. I really hope you didn't pay anywhere close to your EBay asking price for that machine, I normally buy machines like that for scrap price or less.
When you break it all down, the machine is no more complex than your Multicam, with the exception of that turret tool changer. Never seen one like that before, and if a tool changer is not really needed then I would remove it. Too many moving parts, things to go wrong. Other tool change options are available if needed.
Given that all of the wiring seems to be cut, and a lot of electrical hardware seems to be missing from the cabinet, I would just replace the servos with modern hardware, something that has documentation and support. DMM servos would be my choice. https://store.dmm-tech.com/ Given the size of the machine, maybe 1KW servos on the X & Y drives, and a 1.8KW on the Z.
Your control options are endless, but I would take a serious look at the Dynomotion product line. https://dynomotion.com/ Inexpensive, robust, and the support is great.
Really looks like you would be starting from pretty much zero on the control cabinet. For electrical hardware, reuse anything that you can, and you can get the rest from Automation Direct. https://www.automationdirect.com/adc/home/home My preferred vendor for electrical hardware.
If you have some experience with retrofitting machines, then you shouldn't have too much problem with this one. If it was in my shop, I would have it running in a week or so, but I do this stuff for a living so your mileage may vary.
Jim Dawson
Sandy, Oregon, USA