I had a similar problem with a resin-banded 2688 module-based watch that couldn't receive the Colorado signal in Portland, Oregon using Casio's instructions. The solution was to balance the watch on the west more...
The general instructions for the for the 2608 and the 2688 are pretty much the same. However you can go to this type in 2688 for your module number and get specific instructions. http://world.casio.com/wat/download/en/manual/ more...