I am having a similar issue. I tried a couple of condenser mics on random inputs in banks 1-6 and 7-12. Plugged in the mic, turned on phantom power, no signal. I haven't tested every input, but that's my next step. I will also test the cables and mics on another board just to be certain I'm not being silly and using broken equipment. Any other suggestions? I updated the firmware last night and it did not alleviate my problem.