HP 33S Self Test

If the display can be turned on, but the calculator does not seem to be operating properly, do the following diagnostic self test.

1. Hold down the {C} key, then press {yx} at the same time.

2. Press any key eight times and watch the various patterns displayed. After

   you’ve pressed the key eight times, the calculator displays the copyright

   message [Copyright…] and then the message [KBD 01].

3. Starting from first key {ex} on the top left corner of the keyboard and moving from top left to right, press each key in the top row. Then, moving left to right, press each key in the second row, the third row, and so on, until you’ve pressed the last key {+}.

4. The self test produces one of these two results:

   The calculator displays [ -FAIL ] followed by a one digit number, if it

   failed the self test. If you received the message because you pressed a key out of order, reset the calculator (hold down {C}, press {LN} ) and do the self test again. If you pressed the keys in order, but got this message, repeat the self test to verify the results. If the calculator fails again, it requires service. Include a copy of the fail message with the calculator when you ship it for service.

5. To exit the self–test, reset the calculator by holding down {C} and press {LN}.

Note: Pressing {C} and {1/x}, starts a continuous self test that is used at the factory. To halt this factory test by pressing any key.