IBM 6150 Hardware Maintenance Manual page 231

TNL SN20-9843 (03-27-87) to 75X0152 or 75X0166
I Step 6
Be sure the display signal cable is securely plugged into the system unit.
IS THE DISPLAY SIGNAL CABLE SECURELY PLUGGED INTO THE
SYSTEM UNIT?
YES Record SRN 16-410-580, then go to the next page.
NO This completes the repair.
3-5800-6
Service Manual