.....or three!
Having rebuilt my first pack, I managed to get hold of another (much earlier pack - serial number 21xxS) and was rather disconcerted to see it had a three pin contact for the power supply cable rather than the two pin contact I had expected. There is also a copper blade that appears to make contact with the middle pin closing a circuit when the power cable is disconnected.
There was further consternation when on opening the pack I discovered that the metal spring strip contact on one side that conencts with the internal contacts in the calculator does not make contact with the top of the rechargeable battery (as I had expected having rebuilt a 'two pin' pack) but was insulated from it and instead was connected via a flexible ribbon to the circuit board in the pack.
Can anyone enlighten me as to the logic behind the 'three pin' pack?
Now to the rebuild:
One of the metal spring strips which form the connection between the pack and the internal contacts in the '41 was badly corroded and broke in two on removal - any ideas where I can get a replacement? (worst comes to the worst I should be able to use a coil spring)
The printed circuit track on the flexible ribbon mentioned above has corroded away in a number of places and will need replacement - any ideas on a suitable source? (worst comes to the worst I can run a cable from the metal spring strip connector back to the circuit board)