HP-97 on charger only

[isanchez]

(03-18-2020 08:14 PM)teenix Wrote:  

(03-18-2020 01:24 PM)Paul Dale Wrote:  My understanding was that the battery controlled the voltage for the printer.
The charger was sufficient by itself, but the battery helped enough to make it work.

As an aside, I've had no problems with a 67 on the chargers (albeit without loading a magnetic card).


Pauli

The battery directly supplies all the heavy currents for printer motor and heads, card reader motor and LED display. Each sub system has its own regulator to maintain consistent operation. The printer heads are the hungriest drawing at times a few amps, hence the large batteries. The charger won't be able to provide this amount of current.

With the high cost of replacement batteries, I was thinking of adding a second power connection to accept an external 5VDC 3A wall wart for the 97 replacement CPU. These are quite cheap but obviously not portable in this mode.

cheers

Tony

Hi, I have done it. I have implemented a Barrel type (discreet) female connector. With this, I operate the HP97 without batteries inserted, just with a Barrel-USB plugged to a mobile charger (2A). It works really great! It moves the printer & card reader flawlessly. I have done this in three or four HP97. It works also fine with the HP41 series printers...same issue: connector, USB cable, Mobile wall charger...

I enclose a picture of how does it look like...also a brief manual I made for people that requested it from me...I hope it helps...