Help with A2100 extended diagnostics

[TickTock_]

Hi,
I am trying to resurrect a 1995 Milacron Arrow 500 (have a thing for old machines). Machine power will not turn on due to "no CR_AXIS_RDY signal." I have traced the signal all the way through the CMHD High Density IO board to the final octal line driver and it is present. This prompted me to enable the HDIO test in the extended diagnostics window and got the following failure:

High Density I/O Status: Failed
Part Number: CMHD
Diagnostic Version: v 1.05
Hardware Address: 0x00000300
Channel 1: FAILED
Channel 2: FAILED
Channel 3: FAILED
Channel 1 Pattern Written: 8000
Channel 1 Pattern Read: 6ED0
Channel 2 Pattern Written: 8000
Channel 2 Pattern Read: 706E
Channel 3 Pattern Written: 8000
Channel 3 Pattern Read: 0

I am looking for suggestions on how to proceed.

1) Is there a document that indicates what all these bit map to?
2) Has anyone run this test on a working system and can share the results?

When I disconnect J1 & J2 from the CMHD PC card I read 0 for all three channels so this makes me think the problem isn't with the CMHD card in the computer enclosure, but rather on the IO and relay racks above it that are connected via these two cables.

Anyway I would really appreciate any hints or suggestions on what I can look at that would cause all three channels to fail like this.

Thanks!

[TickTock_]

Hope it's not taboo to reply to your own post, but I made progress and wanted to document the finding in case it helps someone else.

Last night, I tried the trick of forcing the machine to stay powered on by holding the green button and got a new, more useful, error message. It said one of the servos was in overcurrent for more then 2 seconds and went into foldback. Based on that I inspected all the servos and noticed the Y was all the way to the limit *and* stuck there (couldn't turn the screw by hand). I opened the access cover in the back of the machine and was able to unstick the screw with a little encouragement. Turned on the machine and things look much better (can jog all 3 axes, ran alignment, and even stepped through a small program). CR_AXES_RDY error message no loner appears. That's as far as I got - I don't have tooling for this machine yet (wasn't going to spend the $$ until I was reasonably sure I could get the machine running) so the program stopped once the machine realized that there was no tool in the spindle.

Just to note, I reran the diagnostic again now that everything appears to be working and as I suspected it still fails although 8 bits did change:

Channel 1 Pattern Written: 8000
Channel 1 Pattern Read: EE8F (was 6ED0)
Channel 2 Pattern Written: 8000
Channel 2 Pattern Read: 706F (was 706E)
Channel 3 Pattern Written: 8000
Channel 3 Pattern Read: 0

My guess is this program was intended more for diagnostics than pass/fail. I also think it would be extremely helpful if only I knew what each bit mapped to!