I recently bought an old HP16C in cosmetically perfect shape - but dead. No batteries. After putting in new batteries it still was dead. No reaction to ON, ON-, ON/D or ON/x. Removed the batteries. Shortened the batteries connector. Put batteries back in. Still no reaction.
Then I shortened the batteries connector with the batteries in the calculator. Surprise: There appeared gibberish in the display - but at least for the first time something appeared in the display, so it seems to be working. With the gibberish in the display I pressed ON/x: the gibberish changed to some other gibberish. Pressed ON alone - calculator went dead again. I opened the back of the calculator, to see if anything was visually wrong inside, but could not find anything. I can repeat all that, except for the gibberish, not always the same gibberish, I get no results. And I cant switch the calculator on using ON.
Does anybody have any ideas what else to try? The serial # of the HP16C is 2530A10022, on the back of the PCB inside it says 20-85 (week/year?). Any ideas, tips, hints etc. will be highly appreciated.
Klaus