Mother-32 problem modulating with Eurorack

[Chrisormitch]

I have an issue connecting the Mother-32 to Eurorack modules. I have a M-32, DFAM, Subharmonicon system, and have not been able to modulate the Mother-32 with anything external like an LFO, or to clock it with a Pam's. When I run any cable from a non-Moog module into the Mother-32 patch bay (or any of the Moog modules in the system actually), the Mother-32 goes silent instantly. I can run sound out from the Moog system to the Eurorack, and can modulate the DFAM and Subharmonicon just fine. I can even modulate the Mother-32 with DFAM and SUB. However, the Mother-32 just cuts out whenever anything external gets plugged into any input in the system.
Nothing in the user manual was helpful. Do I have a malfunctioning module, or am I missing something? Thanks and Happy New Year!