I sold an HP15C on eBay and I am not really familiar with its operation. It did pass the self tests as shown here:
(ON X) and the keyboard test (ON -:-).
See:
http://www.rskey.org/~mwsebastian/selftest/hp_test.htm#voyager
for testing details.
When the winner received it he couldn't even perform rudimentary arithmetic correctly (like 5 ENTER 15 X). I had him clear the complex flag and now that works.
However, both SQRT and X^Y produce ERROR 4. This is confusing because the manual states ERROR 4 is a programming error, I would expect ERROR 0 during a bad SQRT operation.
Thanks for any help you can provide.
Regards,
Victor
Edited: 28 Apr 2005, 1:22 p.m. after one or more responses were posted