I begin a UK tour tomorrow (9.27) in Liverpool, and in rehearsal today my 404 was acting a bit strange

I use a (Roland) drum pad into a TD-3 V-Drum module to trigger samples via MIDI on my SP-404. I've done this (successfully) many times before BUT, for some reason it's not working now. I've tried:
- 3 different MIDI cables
- auto/tempo/off MIDI sync modes
- sending 127 different note #'s from the V-Drum unit ...
not sure what else to try but, it's maddening! I DID recently update the 404 OS - sadly, it hasn't been the same since : ( A N Y insight is
HIGHly appreciated! cheers!