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Full Version: HP-34C switch problem
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My HP-34c turns on fine and works ok; however, when I move the right switch to "PRGM" mode, the calculator turns off.

If I then turn the ON swtich to OFF and back to ON, the 000- digits appear and seem to be working properly (i.e. I can enter a program).

Any idea why and how can this be fixed ? hopefully without opening the case.

I looked into this link but didnt find the answer:


Thank you !

sorry...I meant this link:


Giovanni, I still have my 34C, even if I have not turned it on in a few years now. The last days that it was still somewhat serviceable, I had a very similar problem.

I was more brave in those days, and I opened the 34C (I don't think nowadays I can do so without breaking the shell) and gave the switch contact strip a cleaning with a simple (but clean) pencil eraser, wiping off any dirt, probably rubbing of some of the oxides that may have built up over the years. After that, it worked much better, but only for about a year's time or less.

I tried this because even then, I called HP and they said they no longer had any of the switches on hand and these switches even then were no longer manufactured.

That was then. Now, I would recommend you try FixThatCalc.com or if one of the forum guys with experience with these Spice series HP calculators might want to see if they can do something for you.

Thank you Ed. I will contact fixthatcalc.com first.


DeOxit and DeOxit Gold work great for switches. I use the pen applicator with a slightly abrasive tip. Just scrub it on and it cleans an leaves a protective film.

Thank you John. I will have to open the case after all because the quote from fixthatcalc.com came way too high (for my budget at least).


Well then, be careful and search for information on opening the 34C (or any Spice) shell.