hp 12c


my beloved hp 12c (purchased in 1981) had a cup of coffee today. it still turns on and off, but just has symbols as though you are doing the "on-/" self check.

any ideas how i can get it up and running again?


Your best bet is to simply replace it while 12c calculators are still readily available. Better yet, buy two.


Yes, buy two while you still can. But might I suggest trying to find older stock units. If you go to your local Staples or OfficeMax, you'll end up with newer units made in China and you will see and feel the diffference. The newer units do not have the quality of the orignal 12C's. Try before you buy, if you can.


Randy, do you have any idea when 12C production moved to China? You mentioned in your note that most large retailers are probably selling the Chinese units, but if the production shift occurred recently, then it may be possible that some smaller retailers would still have non-Chinese units in stock.

I would love to get a new 12C, but not if the quality isn't there.



Hi, Scuba;

identifying the new ones is that easy: they use one single 3V button cell instead the 3 x 1,5V LR44-type of the old (good) ones. Just look in the back of the calculator and you'll see the new compartment door (why do Chinese HP workers like to change battery compartment doors? Is it a legacy?). About serial numbers, the Chinese will read CNxxxxxxxxx.



I see you are Kiwi. *Very* nice people and place. On the other hand this puts ebay out of reach. I suggest placing ad for help on the classifieds area - ask for Kiwi help. If you were in Brazil, I am certain you would find some very kind and helpful people to take care of your beloved 12c. Knowing Kiwis, I bet you will find good local help. Good luck, Renato


If all else fails try giving it three baths in an ultrasonic cleaner with fresh distilled water each time. Shake out as much water as you can, then dry in in an oven on low (< 150F) for several days.


Try a good wash with ethannol, it gets into places other cleaners can't, and evaporates away nicely.
I did this with a HP-71 card reader which was completely bunged up with grimy dirt and wouldnt work; after a few good washes with ethanol it works fine and I didn't have to disassemble it!

Possibly Related Threads...
Thread Author Replies Views Last Post
  HP 12C, 12C Platinum & 15C iOS App Walter Lam 2 449 06-02-2011, 01:25 PM
Last Post: Andrés C. Rodríguez (Argentina)
  12C vs 12C Platinum Cash Flows Katie Wasserman 10 941 12-28-2005, 10:12 PM
Last Post: tony(nz)
  12c/12c Platinum programming differences Don Shepherd 6 679 08-11-2003, 10:11 AM
Last Post: Gene
  12C or 12C Platinum...that is the question Joe 3 457 06-21-2003, 11:39 PM
Last Post: Don Nguyen
  What's CPU of HP 12C and HP 12C Platinum Luc Chanh Truong 3 497 06-11-2003, 01:49 AM
Last Post: Vieira, Luiz C. (Brazil)
  Hi !! Gene, HP 12C vs 12C Platinum Luc Chanh Truong 0 274 06-09-2003, 10:28 PM
Last Post: Luc Chanh Truong
  Re: Inconsistent results #1: 12c vs. 12c Platinum hugh 1 314 05-14-2003, 03:22 PM
Last Post: Gene
  Inconsistent Results #2 and #3: 12c vs. 12c Platinum Gene 3 429 05-13-2003, 06:58 PM
Last Post: Patrick
  Inconsistent results #1: 12c vs. 12c Platinum Gene 3 443 05-13-2003, 11:58 AM
Last Post: Vieira, Luiz C. (Brazil)

Forum Jump: