How many batteries ?

From your description the solar cell charges the battery and keeps it topped up. I think the rechargeable battery is the problem because when the screen goes blank the battery level drops to low and the LCD blanks out which would explain the intermittent operation of the watch. I think it is worth getting it checked out with an estimate.

The rechargeable battery needs to be replaced in the watch, you need to take it to a jeweler to have a new one installed.

Is it SOLAR?
I have a Casio Pathfinder, SOLAR, ATOMIC! They have a permanent battery!!!
It must be exposed to the sun occasionally to charge. If yours has nothing on the display, try putting it out in the sun for a day. Put it in a window, sitting on a window sill. Depending on how little charge it has, it may take as long as three days to charge.
Otherwise, the alternative is calling Casio, getting an RMA and sending it to them for a battery replacement.

mcdevito75 here, Possibly the battery is worn out. An old battery will not hold a charge, Visit a small watch repair shop in yourarea for a new battery.

this watch requires no battery. It uses solar cells. my watch did this as well. to make the watch functional again my advice is to not wear the watch for one day and place it near a window that gets a lot of sun.

Check out this YouTube video which walks you through the battery change process:

http://www.youtube.com/watch?v=ogCz2vjUKVg

Change the battery. This happened with mine along with the battery needing charging more frequently. In my opinion, Casio's assertions that you won't need to change the battery is pretty much of a joke. My jewler concurred.

After changing the battery I can now press the light switch button and the watch works normally.

Tony

My watch had the same problem and i could never figure out what it was so i just lived with it for a couple of years. then, just recently even when my watch was getting plenty of sun the battery would die in the evening and shut off at night. so i replaced the battery and evrything works great. even the light which leads me to believe the solar panel is just a gimmick. i have an old g-shock watch that i bought in 1989 and it still works and is on the origional battery. my gw 300 is about 5 years old and needed a battery. i guess 5 years on a battery is prety good but i would rather have it last for 19 years like my old one.

Hey all. The charge provided by the solar cells on the watch only really extend the life of the battery. The total run time of a battery depends on how the watch is used... backlight requirements etc. The battery will be depleted and need to be replaced.

Here is a site that has good instructions on how to change the battery in your G-Shock watch.


http://forums.watchuseek.com/showthread.php?t=20217

If you want to ensure you still have a the same water resistance rating, I do suggest that you take it to a watch guy to have it replaced for you. They clean switch contacts also and you keep water resistance rating. Good Luck and vote this as a "FixYa". Cheers

regards
Graeme