HP HP-28S - 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