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ciao a tutti,

which external power supply can be used safely with an HP71b ?

my guess would be the same as for the HP41 family

but I will appreciate your help

take care, Alberto

Ciao Alberto,

the one that fits into the 82161A will do, in Germany it's the 82066B.



The 82059D works fine with my 71b.

That's the one I use on mine. The output is rated 8VAC/3VA MAX but on I measuring it I found 13.4V (12.6V when the 71B is turned on, but not running). This should be normal since the HP-71B represents no load to the power supply. However the first time I used it one tantalum capacitor blew up inside the 71B (which has not been replaced yet). I don't remember what I did wrong, I only remember I had removed the batteries, but this would not damage the computer, according to the manual. The recommendations in the manual might be useful:

"Turn the HP-71B off before connecting the unit to a power outlet. This will prevent unexpected voltage 'spikes' from disturbing the contents of memory. When connected to a power outlet, the HP-71B uses the batteries as a backup power and normally doesn't draw any power from them. You won't damage the HP-71B by using the computer without batteries, but you may lose everything in memory should there be a power outage or an intermittent connection to the voltage source."

The 82066 is fine in Europe 220V

The 82059 is suitable to the 110V mains.



Not only for the Power Supply, but also to replace a Capacitor,
have a look at the hpmuseum site
ther you can find the 71 Handheld Computer Service Manual
5-13 AC Adapters.


Thanks everybody, very helpful, as always, grazie !!