Chris says:
"I used a small screwdriver right at the top of the clock, and that popped it right out. Wiggled it a bit, and the bottom also came out.
Removed the 2 connectors - the plastic was a bit brittle on one, so be careful.
There are 5 small screws holding the case together - remove these. You'll also need to pop off the "button" in the center of the clock. Pull it straight out.
There are 2 screws holding the switch circuit board together - I removed these to check the voltage going to the lights, but you don't need to do this just to replace
the bulbs.
I found exactly the right bulbs at radio shack - part #272-1092C contains 2 12 v. 60mA wire-terminal base bulbs. The only difference is that the bulbs are clear (the
stock bulbs are frosted). Unsolder the old, and put in the new. You'll need a pretty small soldering iron to avoid melting the switch a bit.
Re-assemble, and reinstall.
Total time: about 30 minutes
Total cost: under $2.00"