HP97 The journey begins

[teenix]

Hi all,

I was trying out the new battery charger board with the HP-25 shell. The charger works fine with the LED going off after full charge.

The battery and charger fit quite nice into the original battery holder and the original spring holds it all snug. The challenge was that the battery and charger need 3 connections to the main CPU board.

This presented a problem because the battery needs to be removed as easy as the original and the flat surface of the spring-loaded battery connector will be happy with 2 pins even if the board sits at a slight angle, but with 3 pins, one might not contact properly. I solved this by using tiny pogo pins with spring loaded contacts.

The battery slips in and out easily and good contact is made.

The attached image shows this, albeit the soldering is a bit awful. It is hard to hold these slippery little pins while trying to solder so I'll have to make a small jig.

The image also shows Daves Woodstock charger plug in position. This connects 5V from the USB port direct to the battery charger and can power the calculator while on charge.

More to fiddle with yet.

cheers

Tony