IBM 5155 Manual To Operations page 56

POST Errors
Find your screen and audio responses in the following
examples, then follow the instructions in the box
marked "Action."
Warning: If the instructions are to have a unit
serviced, and that unit has a fixed disk drive, we
recommend that you back up all disk files onto
diskettes. Normal shipping and handling can result
in permanent loss of data on your fixed disk drives.
Refer to the IBM DOS manual for a description of
the Backup command.
Example 1
Screen Response Audio Response Action
Have the
system unit
.. ..
serviced
Amount of
memory shown
is wrong or no
cursor
1 short beep
30-4 Start
January 1984