HP -28S Manual page 220

Keyboard Test
To perform the keyboard test:
1. Start the test.
a.
Press and hold @ill.
b.
Press
I
NEXT
I.
c.
Release
I
ON
I.
2. The calculator displays
~::E'i'E:OAF.:D
TEST.
a.
Test the first row of the lefthand keyboard by pressing
0
[]J
@] [[]
w
[I].
b. Test the second through sixth rows of the lefthand key-
board in the same way.
c.
Test the first row of the righthand keyboard by pressing
[ill[!
I
DEL
1
~
[!J
W
[EJ.
d. Test the second through seventh rows of the righthand
keyboard in the same way. (Press the @ill key in the correct
order-it won't interrupt the test.)
3. If you've pressed the keys in the correct order and the keyboard
is working properly, the calculator displays
OK-28S. A
message
such as
1
FA I L indicates that you didn't follow the correct or-
der or the calculator failed the test. The number indicates the
nature of the failure.
4. Press @ill.
25: System Operations 219