If the BMDC counts down to zero, it is not laoding the software.
You may want to pull it from its ISA slot and clean the edge connector and/or try a different ISA slot if available.
It is also possible that the software is corrupted or the media (hard drive, floppy, disk on a chip, disk on a module, flash card) is having difficulty being read either because CMOS may not be correct or age.
I would also check the logic power supply. fans, etc.
George
(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)