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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.


Wait a minute, when you open it you can see the PCB? Voyagers have their PCB "gift-wrapped". If yours doesn't have the gift wrap it has been opened by someone before you. Could be in a effort to repair it, or a case of curiousity killed the cat.


Sorry, my mistake. I could see only the back side of the keyboard part of the pcb. Yes, I know. the voyagers are supposed to have a black or white plastic wrapping at the back, but I also read, that the later models dont. This one is 1985. Two springs jump out, when you open the backplate of the calculator. They make an electrical contact with the metal label on the back providing some shielding against electr. fields, I think.

I dont think the calculator was opened before, the rubber feet were in absolut perfect shape. Not any more now, after I lifted them partly...


The springs are normal, my 1983 HP 10C has them too. Mine is "giftwrapped" BTW.

Sorry, no solution to your problem... Perhaps someone more knowledgeable can help out?



can you tell me somthing about the "gibberish" ? Perhaps you know that there are several test-programs in your HP16C. I think it ist ON*,ON+ etc. There is a program which checks the keyboard. If you run this you see parts of the 7 segments on the keyboard. Is this your "gibberish" ?

Andreas Stockburger