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Full Version: Calculator restoration - removing smoke odor from HP-12c
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I am trying to restore an HP-12c (12+ years old) to best condition. Works great, looking pretty good, but it still smells a bit of cigarette smoke. Any suggestions on how to eliminate the odor? I've done external cleaning, and would prefer not to disassemble if possible.

Normally, I use ozone (low concentrations) to de-smoke things. But I'd be worried about oxidizing calculator parts. (Helpful hint: don't ozonate untreated rubber.)

Thanks in advance.


Place the unit about 93 million miles from a very large continuous themonuclear fusion reaction for a few days.

Durn, and I'm just a few miles short of that distance....
Seriously, any likely harm to the LCD from such exposure?

Try a light spray of Nature's Miracle, an enzymatic stain and odor remover. It's mostly water and some isopropyl alcohol so it makes a good, safe, cleaner for calculators. It may require several treaments to rid the machine of the stench. I wouldn't leave it sit too long before wiping dry.

Available at pet stores.

haha, I have some of that stuff for when my dog decides to use the house as a restroom.

Seriously, any likely harm to the LCD from such exposure?
It wouldn't hurt to cut out a little strip of cardboard and place it over the display. I've heard that UV exposure isn't good for LCDs. You'd also want to make certain the calulator's in a well-ventilated spot to avoid too much heat buildup.

Isopropyl alcohol is bad news for the clear plastic window. It will leave white marks behind. Also is not good for the keyboard background.

You can tape over your LCD window if you leave the machine in the sun. I have not had any problem giving it a few days of sun. Probably best to avoid a direct summer Texas noonday sun though.

Instead of covering the LCD, can't you face the calculator away from the sun? If you put the calc upside down, on some blocks for ventilation, the whole calc will get plenty of sun exposure, direct and indirect; and plenty of fresh air, as well.

delete with "delete"

You should let all offending surfaces catch some rays... mayby a calculator rotisserie. Baste occasionally with a nice lemon vineagarette. Serve to Martha Stewart in a pickle tureen.