IBM 6151 Maintenance And Service Manual page 80

15x
RT PC 2MB Memory Expansion Option
Additional Tests: None
Removal Procedure: See Processor, Floating-Point, or System
Memory Removal in Section 4.
Repair Checkout: Run the System Checkout.
16x
RT PC 4MB Memory Expansion Option
Additional Tests: None
Removal Procedure: See Processor, Floating-Point, or System
Memory Removal in Section 4.
Repair Checkout: Run the System Checkout.
18x
Enhanced Advanced Processor Board
Additional Tests: None
Removal Procedure: See Processor, Floating-Point, or System
Memory Removal in Section 4.
Repair Checkout: Run the System Checkout.
3-0020-2 Service Manual