For the first job I had where I had a small amount of influence, the electronics were components being soldered into veroboard. I changed that to use custom printed circuit boards (PCB), and then persuaded to company to buy me a TRS80. That was used for 'development' work on a 4 bit processor that we incorporated into the equipment. I built a parallel interface that attached to our PCB and programmed some battery backed memory that the processor subsequently executed from. Heady days.
Yes, definitely. You would have needed Citroen mineral oil so as not to contaminate the drive hydraulics

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Andrew.