IBM 6151 Maintenance And Service Manual page 261

Step 11
Run the System Checkout using the Advanced Diagnostic Routines.
DIAG·2
The Service Request Number is:
13--521·66B
WRITE .....down the above number.
RETURN .... to the Hardware Maintenance and Service ManuaL
DID THE "THERE IS A HARDWARE PROBLEM IN YOUR
MACHINE" SCREEN DISPLAY?
NO Go to "Step 13" on page 3-0060-13.
YES Continue on the next page.
(6/88) Problem Isolation Charts 3-0060-11