On 06/22/2014 08:36 PM, Mark J. Blair wrote:
  I just got a Digiac model 5504 disk drive exerciser
through eBay. It
 didn't include any documentation. The basic features seem pretty
 straightforward, but I'm hoping to find documentation  to figure out
 the less-obvious stuff, like those "fault enable" switches under a
 locking cover. 
I seem to recall that another fellow pick up one of those a couple of
months back--he posted on the Vintage-Computer forum.  I don't know if
he had documents either.
--Chuck