If the solder wouldn't "stick", you were probably soldering to the remains of the battery. At the ends of the chip are contacts for the crystal (pin 1 end) and battery (opposite end)
This image from my Multi Viper mod (
https://forums.arcade-museum.com/th...xing-konami-viper-switching-multi-mod.432261/ ) shows it clearly (though sharing 1 battery across 3 Timekeepers... of course you can do 1 battery per Timekeeper):
There are several different styles of Timekeeper CAPHATs... that specific style above is the easiest to remove (the top is basically attached by a couple small bridges of epoxy). On the solid blocks, I simply dremel the battery half out of the top, leaving the crystal half encapsulated in epoxy. Obviously you don't want to damage the crystal.
DogP