Over the last twenty years or so, I, like the rest of you, have seen more
than my share of BALLY MPU Boards corroded because of NICAD Batteries. To
eliminate the possibility of this happening to your board, if you are lucky
enough to have one that is not already badly corroded, try the following.
In place of the old NICAD Battery, I purchase a 1 Farad, 5.5Vdc memory type
radial capacitor. It is small enough to mount in the same spot as the old
battery, yet it is strong enough to maintain the voltage necessary to hold
the memory. I personally have tested this, and have been successful even
when the machine was UNPLUGGED for SIX MONTHS! This capacitor is used
extensively in the tele-communications field. You can easily drill two
small holes to accommodate the legs. Insert a small drop of Hot Melt Glue
and the capacitor will remain in place. If you wish, you can secure it with
a cable tie. Then simply run a jumper from the legs of the capacitor to the
appropriate holes on the back of the board. It doesn't take very long to
do, and it will save you many dollars down the road!