Akai S1000 / S1100 samplers

hi list , im new , i just buy an s1100 Akai and i can't connect to a 
scsi device , i  tried to connect to two external disk ,( i have also 
an s5000 and with this , disk is functioning ) but no answer of 
connection from 1100.  always timeout .i set the scsi address to 5 for 
the external disk and 6 for S1100 but nothing
should i connect to the internal scsi connector ? and where i can get 
the power for the hd ?
any suggestion are really appreciate
thanks and merry christmas again
Simone italy