Battery Changing

You need to have a small Philips and/or small flat head screw driver to get into most watches to change the battery. If you buy in the future you probably will get the 4 screws on the back type. Lithium battery (3 volts) lasts 3-5 years typically but on some watches say 7-10 years. silver oxide battery - (1.55 V) - 1 year mercury battery - 1 year - no longer sold in some areas because of hazardous chemicals used. The more the light and alarm is used the shorter the battery life. The above assumes alarm operation for 20 sec/day and one light operation for 1 sec/day. The longer batteries sit on the shelf the shorter the useful life. Save more batteries than you need for say 20-30 years. Plan for others that have not saved. Generalized Digital Watch Battery changing notes: (requirements steady hands, some mechanical experience, and good eyesight)

1. Use plenty of light and a magnifying glass from time to time to see how the components come apart. Don't force anything over its designed strength.
2. Unscrew the 4 screws in the back being careful not to round over the heads of the screws. Usually, the screws are designed to be able to use a Philips or flat head screw driver. The flat head works better for me. Some backs screw on and take a special wrench. A needle nose pliers sometimes fits these slots and can assist in loosening it. Some snap-on type backs pry off by use of a strong knife or small flat head screw driver.
3. Carefully remove the back - for the 4 screw type, note well the orientation of the writing on the back with respect to case or the bands. Reason - there are electrical contacts that touch the alarm crystal and the back case that needs to be put back into proper contact when you put the "back of the watch" back on.
4. Gently remove the rubber seal noting the orientation of how it was installed. This could look like a special formed gasket or be just a O-ring.
5. Study with a magnifying glass (if needed) how the battery is held down. Most of the time it is held in with one screw and clip. In some instances it is necessary to remove the electronics from the case. In this case gently pry it out. Note: don't take the electronics out of the case unless you really need to do so. Care must be taken to not bend the spring switches when it goes back in.
6. Battery removal - Take the screw or screws out that holds the battery down or in the case of no screws compress the clip with a finger nail and pry up a spring end that extends over the side on all 4 corners. This is a metal spring loaded clip that fits over a plastic hook. Do this clarify so as to not break the plastic hook. Note which side of the battery is + and - and how it is orientated as it comes out.
7. Put in the new battery in the same orientation as the one you just took out. This means + and - in the right direction. If this is done within a given number of seconds then the watch will not loose any time. If you take longer than needed or if the watch is stopped then no problem you will be setting the time anyway.
8. Install the battery holder clip making sure it is securely clipped on all 4 corners or install the screw that holds the clip down. Check that the watch electronics is working. If not check the battery holder connections. If still don't work then look for a AC terminal (AC=all clear). If you can find this short + side of the battery to AC terminal with a metal tweezers for 2 sec to reset the watch. Note: on some models pushing the light button will turn on the display for the first time.
9. If you did not take the electronics out of the case then skip to step "9)" otherwise do the following. Push each switch button in the case out as far as each will go. This is to make room to install the watch electronics.
10. Orient the watch electronics with the case. Check by looking at the other side to see that the electronics is going to be put in right side up. Next Line up the watch electronics with the case inserting it part way. Do not force it, this will bend the switch contacts. Now with a small flat head screw driver gently push each spring contact "in" slightly (so as to make contact with the switch) and gently push down on the watch electronics sliding it into the case. Do this for each switch, until the watch electronics is fully into the case.
11. Put the rubber water seal in the same orientation as it came out. To maintain the same amount of water resistance, this should be replaced the same time the battery is replaced. If you use an old gasket and you feel it needs it use a small amount of silicon grease to help seal it. Stocking up on rubber gasket may be necessary for some watches.
12. Install the back in the proper orientation. Writing on the back is usually the same orientation as the numbers on the front of the watch. Screw in the screws. Snap the back on with pressure or a clamp making sure the outer edges of the front are supported.
13. Check each of the switches functions properly and then set the time.
14. Note the date the battery was changed this will help you estimate the life time for this type of battery. When you change the battery during the next 5 years - note how long it last from the time you bought it and stock up on enough for 10-30 years.

In a pinch any battery will work just match the voltage and wire it in from outside. The watch then becomes bulky to ware on the arm as a watch but can still be used as a time reference. A watch with a questionable water seal put in a clear plastic bag will still work fine with the button able to be pushed and the time able to be read. From time to time a small amount of silicon lube applied to the push buttons from the outside could help for sticky buttons and to make the rubber seal more alive. If you own a Timex watch there are instructions for download in PDF of instructions, look under help.

Offered by Mike.