Top tip for Kienzle owners: if you peel off the tape strip on the back, you'll reveal a +/- adjuster, which you can use to make it slightly less inaccurate
Mine's busted like Beatnick's but the glass is broken as well. I don't suppose you could fix it could you?
The thing that normally packs up in the tick-tock type (which are actually real clocks) is the solenoid that winds them up from time to time. May be fixable.