IBM RT PC 10 Hardware Maintenance And Service page 105

Step 37
Step 38
3-60 Service Manual
The Diagnostics 1 (DIAG-1) diskette may be defective. Try a new
Diagnostics 1 (DIAG-1) diskette.
If the new Diagnostics 1 (DIAG-1) diskette does not work, record SRN
12-64A-526 and go to "Step 2" on page 3-6.
A program or machine check occurred. Record SRN 12-986 and go to
"Step 2" on page 3-6.