Problem - HP-97


I ask for help.
In a HP97 with the battery totally full and tested in other 97 when I activate only appears the led indicating that I need to recharge the battery
I thank any help


Hi Gileno,

Have you tried running it on the AC adapter? (with the battery pack in of course). Also, try scrubbing the calculator's battery contacts real good with an eraser, then some alcohol on a cotton swab.

Best regards, Hal


Have you tried running it on the AC adapter?

Yes :-(

Battery contacts

Good :-(

Thank's :-)


What electronic test equipment do you have, and what experience do you have with electronic repair?

The HP97 service manual is on the CD-ROM set. It contains full schematics of the machine.

I'd start by checking the voltages on the Vss (+6.2V) and Vgg (-12V) lines. If the power converter circuit in a Topcat isn't running, the protection circuit tries to bring the battery voltage right down and gets hot-and-bothered in the process!.

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