PB 22/PB 23 CPU Upgrade Information

Warning

Only authorized service personnel should upgrade the system. Anyone who wants to upgrade the system herself/himself should know about the dangers of ESD (Electro-Static Discharge) and the necessary precautions. Unknowingly zapping the components of the computer will void the warranty.

Math Co-Processor

Note

The PB 22/PB 23 systems do not support upgrade processors (ODPs and OPDRs).

The CPU frequency cannot be changed.

WARNING! Do not insert a 20 or 25MHz processor into a 33MHz system.

This system uses a Zero Insertion Force (ZIF) socket; this socket has a lever on the right side of the CPU chip that lifts back and the CPU chip lifts out without any effort. When a new CPU is installed, lift the lever, insert the chip and push the lever back down (also set the jumper).

Jumpers

J27 (Jcpus) Indicates the processor in use.

    ╔══════════════╦══════╤══════╤══════╗
    ║ CPU   (U45)  ║ J27  │ J27  │ J27  ║
    ║ SOCKET       ║ 486  │ 486SX│ 487  ║
    ╠══════════════╩══════╧══════╧══════╣
    ║ PB22 SYSTEMS                      ║
    ╠══════════════╦══════╤══════╤══════╣
    ║ 486DX20      ║ In   │ Out  │ Out  ║
    ╟──────────────╫──────┼──────┼──────╢
    ║ 486SX20      ║ Out  │ In   │ Out  ║
    ╟──────────────╫──────┼──────┼──────╢
    ║ 487SX20      ║ Out  │ Out  │ In   ║
    ╠══════════════╩══════╧══════╧══════╣
    ║ PB23 SYSTEMS                      ║
    ╠══════════════╦══════╤══════╤══════╣
    ║ 486DX33      ║ In   │ Out  │ Out  ║
    ╟──────────────╫──────┼──────┼──────╢
    ║ 486SX33      ║ Out  │ In   │ Out  ║
    ╟──────────────╫──────┼──────┼──────╢
    ║ 487SX33      ║ Out  │ Out  │ In   ║
    ╚══════════════╩══════╧══════╧══════╢