Re: HP71b - which power supply
Message #4 Posted by Gerson W. Barbosa on 17 Aug 2010, 1:47 p.m.,
in response to message #3 by Don Shepherd
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."
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