IBM 6150 Hardware Maintenance Manual page 136

Step 23
TNL SN20-9850 (05-87) to 75X0152 or 75X0166
This step is for flashing numbers only.
Look for the number displayed in the two-digit display in the following
table.
Number
Go to Step
02 "Step 24" on page 3-0030-24
30
"Step 24" on page 3-0030-24
99 "Step 25" on page 3-0030-25
DID YOU FIND THE NUMBER IN THE TABLE?
YES
Go to the step listed.
NO Go to "Step 25" on page 3-0030-25.
(5/87) Problem Isolation Charts 3-0030-23