IBM 6150 Hardware Maintenance Manual page 142

Step 29
TNL SN20-9850 (05-87) to 75X0152 or 75X0166
Be sure the Y cable is correctly connected to the PCA on the IBM 5085
and to the M (mouse) and KBD (keyboard) connectors on the IBM
6150. The PCA is installed in the base of the IBM 5081. If needed, see
the IBM 5085 Graphics Processor Maintenance Information Manual.
DID YOU FIND A PROBLEM?
YES This completes the repair.
NO Go to the maintenance instructions for the IBM 5085.
(5/87) Problem Isolation Charts 3-0030-29