This achievement is story related and can't be missed.
*** Spoiler - click to reveal ***After getting take the hamster out of the vacuum cleaner hatch and put it into the generator again. If you don't have it already, get the extension cord from the 70's mummy room. The extension cord is behind the mummy in a plug next to the pink flamingo.
Use the extension cord in the outlets on the hamster generator, and then use the cord on the window to get it outside.
Outside go to the Chron-O-John to plug the cord in the extension cord.