Casio illuminator, w-94h

CTL1616 and there is a video on you tube showing you how to do it.

I assume this is the casio Forester.

Hi Jennifer

Two possibiities here one is electronic, unlikely but possible, and one mechanical that you can check.

When you changed the batteries did you notice internally the location of the button that turns the back light on? If you pressed the light button, did the button or a spindle move forward towards the body of the watch? did you notice a contact? or nothing pressed against anything?

When changing the batteries you would have click open the battery holding frame. This frame or internal back plate has around the light button a little piece of metal, like a finger that gets pressed by the button towards a contact in the body of the watch. This finger suffers metal fatigue and quite often looses its springiness or snaps altogether and loses it ability to make contact between the frame and the EL plate that illuminates the back of the watch.
If you are missing this contact perhaps you could buy a replacement plate from Casio. Can not advise as to the costs of doing it yourself or sending it to Casio. It is fiddly job.
Hope this helps

The Casio Forester FT500WVB watch has an EL (Electroluminescent) backlight and requires one silver oxide button battery. The SR621W battery (also known as type 363) is recommended by the instruction manual for the watch. Note the suffix "W" means this battery is a high drain type which is suitable for powering a watch mechanism and the EL light as well for 2 to 3 years, depending on use of the light. "SW" suffix batteries are low drain and are intended only to power a watch mechanism, and not a light. Note also the "SR" prefix indicates the battery is silver oxide and not lithium. The SR type batteries do not use mercury and are therefore safer to dispose of when they are discharged. I have found the type SR626W (also known as type 377) battery is also suitable for the FT500WVB watch and it has more stored power and should therefore last longer.

Last, the Casio Forrester FT500WC looks exactly like the FT500WVB, but it is a different watch internally. The FT500WC has an LED light and requires two batteries- the SR920SW low drain silver oxide battery which powers the watch mechanism and the CR1616 lithium battery which powers the LED. The LED is brighter than an EL light and stays on longer than the EL light when activated. But the LED has a bright dot light source that some might find annoying.

have you had the back off the watch

Casio AW43:
clock battery - SR920W
backlight battery - CR1616

CTL is the designation for a rechargeable secondary battery. The CR is a primary disposable battery and is a 3 volt cell. The CTL1616 while the same size as the CR1616 function completely differently and are not interchangeable. The CTL1616 is 2.3 volts and is recharged by solar or light or kinetic movement. The CR1616 is 3 volts is not rechargeable and will not function properly in a time piece designed for a 2.3 volt circuit. There is only one manufacturer of the CTL1616, Panasonic and they sell through Casio parts distribution.

This sounds like a simple battery replacement. Depending on how low the battery is usually pressing the light button and the display goes dim or blank is a good indicator of this. Takes a CR1616 battery and be careful of the spring inside and make sure the seal is in the correct position. You will need to touch the AC button and the back of the battery with a pair tweezers for a couple of seconds to reset the watch. Put the case back on and set the watch thru the functions.

Hi, release the small screw and turn left or right remove old battery and replace new one .

Hold down the "Adjust" button (top left) for three seconds. It won't adjust unless you hold the button down.

Press "Mode" (bottom left) to change what you're adjusting, seconds, hour, minute.

Press the top right and bottom right buttons to adjust the number up and down.

Press "Adjust" again when you're done setting the watch.

To change date, alarm, alternate time, etc, press "Mode" to get to those functions before hitting "Adjust."

I hope that helps.

Hey all, here is a site that has good instructions on how to change the battery in your G-Shock watch. Sounds like you are suffering a low batt problem.

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