IBM 6150 Hardware Maintenance Manual page 297

Step 4
The problem may be the diskettes.
1. Get a different set of diagnostic diskettes.
2. Try to run the failing diagnostic test.
3. When the test completes or stops, look at the bottom of the display.
DID THE MESSAGE "DIAGNOSTIC ERROR - Diskette error"
DISPLAY?
NO Replace the failing set of diagnostic diskettes. Go to "Problem
Determination Procedure PIC 0030" on page 3-0030-1 and get
another SRN.
YES Continue on the next page ..
3-9860-4 Service Manual