I have the ??c bought in .. er ... 1983 was it? It's a ??c instead of a 10c or a 12c because the badge thingie fell off and now I can't remember the model number. It put me through stats at Uni. Also, a pair of the 32s model from maybe 1995 or so. All three work just fine, except that one of the 32s units has some missing pixels. I just had the passing thought that a desk-mounted RPM calculator would be easier to find. I am forever losing the three pocket ones. But mostly, these days, I don't use them, just do it in my head.
And why an RPN scientific calculator for working out the price of three sticks of RAM and a hard drive upgrade? Because orthodox notation sucks! RpN ruLeZ!