To revive a HP-97

[Jose Ernesto]

I'm trying to revive a HP-97 I got from a friend. I bought the cells to assemble a new pack, but I couldn't find a suitable power source. What I have is an 6 V AC x 3 watts power source, but all I can get is a big red dot on the display. I understand that this means that power is low, even if the source is connected to the unit. I wonder if 6 V is too few, maybe the 97 demands a little more. Does anyone have an idea of these power levels?
I couldn't even begin to test the rest of the calculator, but I've noticed that the card reader needs repair and I was unable to check the printer.
Thanks

[David Smith]

The HP97 power plug is rated around 9VAC at around 300mA. The actual volatge seems to be around 12V under light loads. The plug transformer has a fairly high output impedance that helps serve as a current limit function. You can find the plugs (82059 series) very regularly on Ebay. They are the same ones used by most of the HP41 printers and accessories.

The HP9x machines do not work properly without a good battery pack installed.