HP -22S Owner's Manual page 148

3. If the calculator fails to respond after steps 1 and 2, remove
the batteries (see page 143) and lightly press a coin against
both calculator battery contacts. Put the batteries back in and
turn on the calculator. It should display
MEMORY CLEAR.
If steps 1 through 3 fail to restore calculator function, the calculator
requires service.
• If the calculator responds to keystrokes but you suspect that it
is malfunctioning:
1. Do the self-test (described below). If the calculator fails the
self test, it requires service.
2. If the calculator passes the self-test, it is likely that you've
made a mistake in operating the calculator. Try rereading por-
tions of the manual, and check "Answers to Common
Questions" on page 140.
3. Contact the Calculator Support department. The address and
phone number are listed on the inside back cover.
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.
1. To start the self-test, hold down the @] key while you press
[Z].*
2. Press any key eight times, and watch the display as various pat-
terns are displayed. After you've pressed the key eight times, the
calculator displays the copyright message
COPR. HP 1987,
and
then the message
K B 0 01.
• Holding down
@]
as you press 11
Ix
I
starts a continuous self-test that is used at the factory.
If you accidently start this self-test, you can halt
it
by pressing any key.
148 A: Assistance, Batteries, Memory, and Service