Introduction
About a year ago, my
"Casio Pro Trek PRG-50" suddenly failed — after only a few years of operation, despite the
"Tough Solar" power system.
The Tough Solar Power System
Casio gives the impression that you will never need to worry about replacing batteries (
Tough Solar Power), or ever worry about the life of the solar cell and rechargeable battery (
Tough Solar FAQ) that
"should be able to last as long as the watch". Amazon claims that
"[...] Tough Solar power (uses ctl1616 battery you will never need to change)[...]" (
Amazon 2007). However, my watch clearly failed to recharge.
The Panasonic CTL1616 battery
Opening the watch, it was easy to spot the problem. The
"Casio Pro Trek PRG-50" uses a
"Panasonic CTL1616 2.3V" rechargeable battery, and the battery was clearly eroded. It turns out that I'm not the only one that have had this problem (
Another Tough Solar with a Panasonic CTL1616 fails.). The front of this old battery says
"+, Panasonic, CTL1616, JAPAN", and the back says "27".
I ordered a new CTL1616 battery, $8.50 each, from American Perfit (
http://www.ctl1616.com/). Sunday, 29. April 2007 — and received it in Norway, after only 6 days, Friday 04. May 2007. Notice that
"JAPAN 2" is printed on the new battery.
"The original battery has the letters JAPAN without number 2 engraving." (
asuoab 2006).
Opening the watch
Do not open the watch! There is a lot of small parts that you will most certainly lose. If you still insist on opening your watch, knowing full well that you are going to totally destroy it, please work with your watch inside an empty plastic box or similar, so that when you drop all the small parts, you may perhaps find them again if you are lucky.
The back can be opened after unscrewing 4 irreplaceable screws. Put them somewhere safe, and be carefull not to drop them.
Be very careful when opening the watch — and under no circumstances try to turn the watch around — because 4 tiny irreplaceable springs may disapear (asuoab 2006, Sjors 2006). asuoab (2006) indicates that loosing the springs will cause the watch not to charge the battery - following by all sorts of problems.
Replacing the battery
A clasp holds the battery down in place — use a needle to unlock the clasp (Sjors 2006). A plastic tweezer should be used when handling the battery, avoiding the battery to short circuit.
Charging the Battery
Oh, and of course you should wait for a while before using the watch until the new battery is fully charged!
Conclusion
Does the watch still work? Yes, every function on the watch seems to work OK. As far as I can tell, the watch has run perfectly since Friday 4 May 2007 — and I'm going to tell you right here when it stops working correctly (still no problems, 22 May 2012). The watch was not reset as described by asuoab (2006) and Sjors (2006), but worked anyway. The watch was not cleansed, and no silicone lubricate was used, which may cause the watch to be less watertight. asuoab (2006) and Sjors (2006) describe how to perform these steps.
References
Resources
