A couple of weeks ago my sister dropped of a nice George Nelson starburst quartz wall clock that wasn't working. I put in the spare room and forgot about it.
Tonight I saw it and decided to open it up and see what was wrong. It can only be 2 things, a bad motor or misaligned gear train.
If you've never opened a quartz clock mechanism, you'd be surprised at how simple it is.
It's only 6 gears and the main shaft. The hard part is getting the hands off without bending them. Oh, and remembering the gear order when you put them back.
I got lucky, the motor still ran so apparently one of the gears had slipped out of position when she moved it or jarred it.
After about 20 minutes, it's back together and running like, well, a clock.
Attachment 95006

The clock is 19" across with a 6 1/2" face.
The only tools required were a pair of needle nose pliers, tweezers, and a flat blade micro screwdriver to open the case.
It will replace the 19" red starburst in the living room
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and the red one will go into the kitchen to replace the small retro unit that's there.