Digi 002/003 output levels too high

[kokobeware]

I work in 3 studios.

-one has a digi 002
-one has a digi 003
-one has a mbox pro 2

-all three are connected to the Mackie Big Knob with balanced cables

-the two studios with the digi 002 and 003 show output levels way over 0 on the Big Knob and I can only get them back to 0 by turning the input gain on the back of the Big Knob -10. Also the +4 switch is in the right position on the Big Knob.

-the studio with the mbox pro 2 works perfectly, peaking at 0 on the Big Knob and keeping the input gain at 0 on the back of the Big Knob

any suggestions?