Picked up a Canon Motor Drive MF for my (relatively recently) acquired Canon F-1. Guy I got it from said he hadn't used it in the past 10 years. When I first tried to fire it up, no joy. But its circuitry must've simply been asleep as I kept at it and did get it to fire... it then "rested" a few second before it would fire again, rested a bit more, then was able to fully function on both "C" and "S."
I have the Canon Power Winder MF, and I had the same problem when I first bought it, I put some new alkaline batteries in it, and kept turning it on until it started to work reliably. I've had it about three years now, and it's been O.K since.