IBM 6150 Hardware Maintenance Manual page 132

Step 19
TNL SN20-9850 (05-87) to 75X0152 or 75X0166
Some problems prevent the diagnostic diskette from loading and the
Operating System loads instead.
Look at the display and determine if a screen from the customer's
operating system is displayed. If needed, ask the customer for assistance
in determining the above condition.
IS A SCREEN FROM THE CUSTOMER'S OPERATING SYSTEM
DISPLAYED?
NO Go to "Step 21" on page 3-0030-21.
YES Continue on the next page.
(5/87) Problem Isolation Charts 3-0030-19