IBM Personal Computer AT Manual To Operations page 391

16
Wait for the Power-On Self Test (POST) to
complete. The IBM Personal Computer BASIC
message will appear with a blinking cursor (if an
operating system is not loaded from a diskette or
from the fixed disk drive).
The IBM Personal Computer Basic
Version CX.XX Copyright IBM Corp. XXXX
XXXXX Bytes Free
Ok
1LIST 2RUN 3LOAO" 4SAVE 5CONT 6LPT1 '7TRON BTROFF 9KEY OSCREEN
17
Is your screen blank?
YES Have your system unit serviced. Be sure
your Key Lock key is with your system
unit.
NO Go to Step 18.
Test 9000-9