My HP 35 works only with charger

[John R]

(02-19-2015 03:24 AM)Den Belillo (Martinez Ca.) Wrote:  I've had the same problem. The first thing to check is the contacts, because it's easy and out in the open. Hit them with an ink eraser or lightly with some scotchbrite. A bit of contact cleaner might be good too. Good luck.

I have an HP-80 with this same problem. Cleaning the contacts on the back of the calculator (i.e., the gold posts and tongue) with isopropyl alcohol fixed it for a while. Like time, however, oxidation matches on, and the problem has recently recurred. I have been meaning to try some DeoxIT Gold but haven't gotten around to it yet....