HP41c battery pack refurbished with micro USB connector.

[isanchez]

Thanks, Ángel & Massimo! Very proud to recieve your congrats!

On the other hand, and following with the "avoid batteries and chargers" philosophy, I have done a similar project for HP 41C printers and HP97 family calculators...

In both cases, the solution is the same: I have added a discreet coaxial "5.5mm barrel type" plug in the back of the Printer/HP97.

Using a cable with "Barrel Type" connector and with a conventional USB at the other end (easy to find in amazon).. This gives power to the HP97 and printer without the need of a battery pack installed or a original charger. It can be plugged to any Ipad/mobile charger or to a USB 2.0/3.0(better) laptop port.

As an altenative, a conventional 5V regulated charger can be used (with 5.5 mm coaxial end)

It is important to remark that the old powering system is not lost at all: you can use this new standard system, as an alternative system to power your printer/calculator.

If any detailed information required, please ask me!

I enclose some pictures.

Regards

Ignacio