This can easily be repaired if you (or someone you know) are handy with a soldering iron...it'll more than likely be the "micro-switch" that's knackered due to mechanical shelf-life (they don't last forever) and these things cost peanuts on Ebay.
Snip the 4 legs off with a pair of sharp-side-cutters or just get a small flat bladed (jewellers screwdriver) tool behind the "pins" and snap em off...chuck the switch and you can now de-solder (or use solder wick) the leftover pins from the switch...this will leave you with 4 neat holes...pop in a new switch, solder the pins...fit the board back to your grinder...enjoy coffee
