I started the CNC improvement project. I was working on some things in this project. Here is the status:
Disassembled the controller. I can see now what is roughly inside.
Exchanged the fan. Most probably this was one of the easiest task.
Searching on the net I was able to find drawings for the stepper driver/PC interface board. I can start from it.
Based on the drawings I set up the E-Stop (Emergency Stop) button and the PCB leveling probe. From this one I don't like to use the original one, so I bought a plug and some cable to create mine.
I collected everything what I need for the external PSU: bought an enclosure, connectors and the switching PSU modules are also arrived. I designed the layout of the front and back panel, just the drilling, milling and wiring left.
For the rotational speed measurement I removed the original "fan" from the top of the spindle drive and designed a replacement part, what has an encoder ring in addition. For this one missing a PCB what will hold the optocoupler and some part to hold this PCB in it's place. I can manufacture this ones when I'll be able to bring my 3D printer back into life.
I also published this design to the thingiverse: