[albee1952]

Assuming this is an HD IO 16x16 analog? Open Setup>Hardware and verify that 9-16 inputs AND outputs are set to +4(or the same as 1-8). I would also try swapping the DB 25 connections to see if the problem follows the cable or remains with the IO(1-8 or 9-16).

Last thing(and really important), if you attempted(on purpose OR by mistake) to run UNbalanced signals, the manual states in bold letters that this will damage the unit if the cold side(the "-" of the balanced line) gets grounded(this could happen if you had DB25's routed to a 1/4" patchbay and connected with an unbalanced cable(TS instead of TRS).