Lets do this one at a time. Work with 1 drive at a time with the first drive output and see if it boots.

Like TechKnight says - Control Reset should get you to a BASIC Prompt.

Put in a DOS Disk (make sure its a back up and not your original!) in to the drive and type

PR#6 [RETURN]

That will reactivate the card like a cold reboot, and see if the disk boots.

Turn off and swap the drive and repeat.

Note: I just noticed that one of the chips has a date from from 1993! So this had to have been fixed more than one time. Probably from a previous owner plugging in the drive the wrong way more than once!