PB400/PB401T Cache 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.

Cache

Use SRAM chips with 28 pins.

Cache memory can be purchased from PACKARD BELL end user service, at (801) 579-0160.

256KB (1-32Kx8, 15ns, 1-64Kx1, 15ns and 8-32Kx8, 20ns SRAMs)
128KB (1-32Kx8, 15ns, 1-64Kx1, 15ns and 4-32Kx8, 20ns SRAMs)
64KB  (1-32Kx8, 15ns, 1-64Kx1, 15ns and 8-8Kx8,  20ns SRAMs)

Jumper Settings

    ╔═══════════════╤════╤══════╤═════╤═════╗
    ║ JUMPER        │PIN │ 0,64K│128K │256K ║
    ╠═══════════════╪════╪══════╪═════╪═════╣
    ║ J36 (Jcach)   │1-2 │  Out │ In  │ In  ║
    ║               │3-4 │  Out │ Out │ In  ║
    ║               │5-6 │  Out │ In  │ In  ║
    ║               │7-8 │  Out │ In  │ Out ║
    ║               │9-10│  Out │ Out │ In  ║
    ╚═══════════════╧════╧══════╧═════╧═════╝

Surface Mount Configurations

    ╔══════════════════════╦═══════════╤════════════╤════════════╗
    ║ SOCKETS              ║   64KB    │   128KB    │   256KB    ║
    ╠══════════════════════╬═══════════╪════════════╪════════════╣
    ║ Tag SRAM 15ns (U81)  ║ One 32Kx8 │ One 32Kx8  │ One 32Kx8  ║
    ╟──────────────────────╫───────────┼────────────┼────────────╢
    ║ DB SRAM 15ns (U84)   ║ One 64Kx1 │ One 64Kx1  │ One 64Kx1  ║
    ╟──────────────────────╫───────────┼────────────┼────────────╢
    ║ Even Bank Cache 20ns ║ Four 8Kx8 │ Four 32Kx8 │ Four 32Kx8 ║
    ╟──────────────────────╫───────────┼────────────┼────────────╢
    ║ Odd Bank Cache 20ns  ║ Four 8Kx8 │   EMPTY    │ Four 32Kx8 ║
    ╚══════════════════════╩═══════════╧════════════╧════════════╝