HP HP-20S - Confirming Calculator Operation-The Self-Test

Confirming Calculator Operation—
the Self-Test
If the display can be turned on, but it appears that the calculator is
not operating properly, you can do a diagnostic self-test. To run the
self-test:
1.
116
First, hold down the key, then press and hold (y*]. (A continu-
ous self-test can be performed by holding down as you press
(1/x]. This test displays various patterns and the copyright message,
then automatically repeats. The test continues until you halt it by
pressing [C].)
Press any key four times, and watch the display as various pat-
terns are displayed. After pressing the key four times, the
calculator displays the copyright message COPr. HP 1987 momen-
tarily, and then the message 01. This indicates the calculator is
ready for the key test.
Starting at the upper left corner ([(Jz]) and moving from left to
right, press each key in the top row. Then, moving left to right,
press each key in the second row, third row, etc., until you've
pressed each key.
B If you press the keys in the proper order, and they are func-
tioning properly, the calculator displays two-digit numbers.
(The calculator is counting the keys using hexadecimal base.)
B If you press a key out of order, or if a key isn’t functioning
properly, the next keystroke displays 20 - FAIL, followed by a
one-digit number. If you received the message because you
pressed a key out of order, you should reset the calculator
(hold down and press [LN]) and start the self-test over. If
you pressed the keys in order, but got this message, the calcu-
lator requires service.
When the keyboard test has been completed, the calculator dis-
plays a message:
B The calculator displays 20 - Good if it passed the self-test.
B The calculator displays 20 - FAIL, followed by a one-digit
hexadecimal number 1 through F, if it failed the self-test. If
the calculator failed the self-test, it requires service (page 118).
Include a copy of the fail message with the calculator when
you ship it for service.
Assistance, Batteries, Memory, and Service