I have casio watch 2515..i change the battery but it didnt work..

SOURCE: Changing the battery on My Casio watch module 1848. Two

The contact springs most likely have nothing to do with your screen being black.
The watch will have an "AC" or all clear function that needs to be performed. Check the back lid for AC or reset instructions. If there are no instructions there then you will have to visit a watch repairman/technician to have this procedure performed as it involves touching the AC pad on the circuit board to the back of the battery already installed. The circuit board is easily damaged if not performed properly.

SOURCE: Casio Waveceptor 2734 WVA-105H watch not working

You can use the manual to manually reset the time. After you succeed in setting UK time zone, wait until midgnigth: it should synchronize itself with the time signal from Germany. If unsuccessful to do so, it will keep attempting to synchronize itself at 1, 2, 3, 4, and 5.

Read the manual to figure out how to place the watch on a window sill. It might be better to be outside.
Keep in mind that the success of the operation depends on meteorological conditions.
Good Luck.

SOURCE: Casio DBCW150-1 Databank watch (battery change)

DONT THROW IT AWAY THAT IS A COLLECTORS ITEM... You can get it taken care of at www.casiowatchrepair.com or call them toll free 877.659.0761 and have them take care of it, the watch will be as good as new.

SOURCE: I have a Casio DBC-60. I changed the battery because was not working for long time, but the watch stil is not working

This is an old problem, but maybe this will help someone changing a battery on a Casio. Many Casio watches must be "zeroed out" by putting an pointed tweezers between the back of the battery and the AC terminal off to the side of the battery. On my old Casio Telememo 50, the AC terminal is in a very small hole just above the battery. On the Baby G force, it was in a wider opening, way at the edge of the watch. It has something to do with resetting the watches circuitry so it will operate again. Good luck!

SOURCE: Casio 1170 ATC-1200 watch needs to have batteries changed

I'll post in case somebody still needs this. This is the general procedure to switch the ATC 1200 from meters to feet. You can also switch the ATC 1200 (1170) from C to F. This is very helpful if you change the batteries and the watch gets reset to meters.

Also note, when you pull out the two batteries, you may not get the watch to come up. This is because of a race condition when the watch gets power. To fix this, look for the AC mark on the inside of the watch. Under this marking, in a little space to the left, are two copper pads. Short this out with a small screw driver to get the watch to ground zero.

To fix the Metric measurements:

1. Go to the home screen on the watch. This is when the the 3 letter abbr for the day is at the top. Also, if you cycle the mode button, it is the screen where the final beep is "high."

2. Then press the "memory" button, which will take the home display to the data screen. This shows current time, pressure and temperature.

3. Hold down the adjust button, until the set screen comes up.

4. Tab the mode/select button on the watch until you get a flashing C. Then press the memory button to toggle to F.

You can adjust all the measurements from this screen.