Hi Keith,

-The word "Disk" must programmed into the video EPROM so I now know that the instructions are the same.

Just for info: All text on the screen is stored on the CPU EPROM's in a data field, the video EPROM stores the character set.
I made some extensions for my C5 with the EPROM file from Kapsi Ketturi, I can now display lowercase letters and a lot of special characters
because I can load a comment which is displayed on the MAN screen. (workpiece name, tools etc, this nearly empty screen must be used :-) )
and it is better readable with mixed characters; all this just for fun, I like experimenting. (the special characters from EMCO are untouched of course)

https://ketturi.kapsi.fi/2017/10/reverse-engineering-emco-cnc-video-controller/

So EMCO made however some modifications to the source code. Do you have the possibility to readout the CPU EPROM's,
I am curious about the differences between tape equipped and disk C5.

By the way you would have a backup of the EPROMS in case they fail.

Dieter