My lab partner in college had a brand new HP-45. He got annoyed that everyone wanted to borrow it for homework, so he took it apart and swapped the SIN and COS chicklets. He told a few close friends, but everyone else never figured out why they kept getting wrong answers.
Those HPs were built like bricks. My lab partner once accidentally ran over his calculator with his car and it still worked.
I had (and still have) a TI-50. Not quite as good, but about half the price of the HP ($150 versus $300 or so). One day I should get some new NiCad cells and rebuild the battery pack.
