Fired up this Televideo PM/286 to find that the hard drive was suffering from "stiction", the slang term used to describe the condition where a hard drive's platters are not able to spin due to hardened lubricant grease. The hard drive can be seen to the right of the disk drive, positioned on its side. In order to get to the drive I had to remove a number of screws and stability braces. Being business systems, the PM/286 was meant to be be serviced by authorized Televideo techs.

After a thorough cleaning, and hard drive de-stiction (open cover and rotate counter-clockwise a few turns), I was able to access the hard drive. As a test I installed the Televideo AT graphic demo to the hard drive (Televideo DOS 3.1).