Chris,

I've got several of these board sets, and I was just playing around 
with one last night.  It, too, had been set to the secondary address 
like yours, and when I tried to reset it to the default, I forgot
to change the jumper (after just posting this information!). Anyway,
I just checked 4 different boards, and the jumper is there on all of them.
It's on the M7164, the same one with the dip switches, just above 
the second "hand" that inserts into the bus.  The label below says
"W1  TP5".  With the default configuration, the jumper looks like this:
   |---|
   | o |
   |   |
   | o |   o
   |---|

  W1    TP5

At the secondary address, it looks like this:

     o
  |-----------|
  |  o     o  |
  |-----------|
  W1      TP5

I spent about an hour last night trying to figure out why my 
KA650 would hang in the Boot Prom test, until I remembered to 
set this jumper to the first position above.

I'm not sure, but I think that the second diagram above is equivalent
to having the jumper removed, which may be your case.  Then all you 
need to do is go grab a jumper from one of those dead ESDI drives you
probably have lying around, and stick it on.

Doug