|Re: OT: Canon Pocketronic rebuild advice|
Message #3 Posted by Katie Wasserman on 9 Jan 2011, 11:21 p.m.,
in response to message #1 by Michael Meyer
I have a couple of Pocketronics and a Monroe 10 (the same thing in a slightly different case). Like you, I've retrofitted virtually all my calculators to use Energizer lithium cells.
The Pocketronic uses two voltages : 7 x 2/3AA nicads (8.4 volts nominally) and 6 x AA nicads (7.2 volts nominally). The trick is to come up with battery holders for AAA size cells that can both fit in the provided spaces and can be wired in series to provide adequate voltages. I was able to do this using the following (I'm doing this from memory, so don't hold me to it):
1 2xAAA holder where the cells are front to back (not side by side)
2 1xAAA holders (side by side)
1 4xAAA holder (side by side)
1 3xAAA holder (side by side)
(Mouser sells these, the 2xAAA holder front to back is hard to find elsewhere.)
That's a total of 11 cells: 6 for the 8.4 volt nominal supply and 5 for the 7.2 volt nominal supply. There's only one way you can position these 5 battery holders in the Pocketronic cavities but there are several ways you could wire them up in series -- have fun with that!
Also, in case you loose track of the current wiring in the process of replacing the cells, it's this:
violet color wire is the common for both voltages
green color wire gets +7.2 volts
orange color wire get -8.4 volts
The craziest color scheme I've come across in a calculator but they are very consistent from unit to unit (I've rebuilt several of these over the years) even in the Monroe 10.
Edited: 9 Jan 2011, 11:58 p.m.