Posts: 899
Threads: 193
Joined: Jan 2005
The website below has lots of info about the 12C
http://www.hp.com/calculators/financial/12c/
Posts: 121
Threads: 26
Joined: Jul 2005
I doubt that your calc is 12C because 12C doesn't have transcendental functions built in thus no [deg, rad, grd] mode exists on 12C. If it is indeed one of the Voyagers it has to be either 11C or 15C. You can say which one if you look at the second key above Enter key. If it has MATRIX written in yellow above it then it is 15C. If it has (Greek) PI written above that key, then it is 11C.
To get rid of USER mode just press and release [f] (yellow key) and [RCL] key (third to the right of [f]). To switch from radian mode back to degrees (get rid of RAD) press [g] key (blue key) and [7].
Sadly, there is no on-line documentation for either 11 or 15C, but the full manuals are available on the museum CDs (DVD) for ~$30.
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