Might want to check your analog cable connectors, and see if there's a dirt/corrosion issue (unplugging and replugging several times often self-cleans the rectangular
cinch-jones connectors used on the
Leprecon equipment). Also, check the output of the
console, and see if you're outputting 0-10 volts dc, which is what the MX dimmers will be looking for. Not all analog systems used the same range, although problems with this usually manifest themselves in terms of
dimmer curve, not flickering.
Dirty or bad faders in the
console may also be an issue. Does the problem follow if you start swapping packs around, or put the old dimmers back in place?
Since you're not mentioning problems like
dimmer coming up out of sequence, or levels changing as additional
dimmer are added, I'm assuming that your pinouts on the control cabling is correct.