An old employer of mine called me the other day to ask if my new business could use a CNC mill... it is actually the Fadal 4020 that I learned to run/setup and later program almost 20 years ago.

Generally it looks to be in pretty good shape, though it does seem he's been getting casual with the maintenance on this machine, knowing that he'd be replacing it soon. Everything looks good, but the X axis has a little slop in it 001 to 002. I'm betting the thrust bearings need a little TLC. No problem.

The potentially bigger issue is that he says that a couple times in the last few months, while the machine was going through its warm-up program in the morning, the Z came down and bumped (violently) into the chuck. Of course no one was watching to see exactly what happened, so there's not much to go on there. I was in the shop looking at it today and we ran the warm up for about 40 minutes, and don't you know, it failed. It didn't send the spindle sailing into the table or anything, it just shut off and quickly reset the whole machine... as if it completely lost power for half a second. The screen went blank, then up pops the 'home all axes..." start up screen. I hit JOG, as if recovering from an E Stop, and everything seemed fine, it just blipped off.

The faults page reported AXIS CONTROLLER DOES NOT RESPOND TO NC, but I think that's a symptom of the power blip rather than the cause??

The seller is a real stand up guy, and he told me about this well in advance, plus he's giving me a really good price for a machine that otherwise runs really nice.

Any thoughts on what I'm looking at here? Maybe a power supply or axis card pooping out?