PowerBook 145B-series

Motherboard Diagram by MacGurus
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The PowerBook 145B has a single motherboard expansion slot addressed along a 32-bit memory bus. This computer requires standard 100ns pseudostatic RAM modules (PSRAM) in either 2MB or 4MB capacities, as it shipped in a 4MB default configuration with one vacant expansion slot. While the PB145B accepts memory that is compatible with the earlier PB140, PB145, and PB170, it would be helpful nonetheless to mention the model number in the Comments field of the order form when purchasing PSRAM upgrade modules.

With 4MB PSRAM soldered to the logic board, the PB145B is bootable out of the box. The addition of a single 2MB or 4MB expansion module yields memory configurations of 6MB and 8MB. The maximum amount of usable memory in the PB145B is 8MB, in the form of a single 4MB module in combination with the soldered 4MBs of logic board PSRAM. It is significant and characteristic of this computer's ROM that it can accept a 6MB PSRAM module (for a total of 10MB including motherboard PSRAM), yet only recognize and use a total of 8MB.

While the PowerBook 140, 145 and 170 all share a common motherboard architecture with 2MBs of soldered PSRAM and a 2MB PSRAM expansion card, the PB145B includes 4MB of soldered PSRAM, which enables expansion beyond 4MB without the necessity of wasting a 2MB PSRAM expansion card. The Motorola 68030 on the PB145B daughtercard runs at 25 MHz, but lacks a Motorola 68882 FPU. One peculiarity of the PB140, 145, 145B and 170-series is that they do not support SCSI Disk Mode. All four of these PowerBooks address memory along a 32-bit data path.


Specifications
Logic Board PSRAM 4MB.
Supported Modules 2MB, 4MB.
Number Expansion Slots One (1).
Supported VRAM None.
Number VRAM Slots None.
L2 Cache Supported None (Non-PowerPC architecture).
Module Type 100ns Pseudo Static RAM (PSRAM) Card.


While some of the products mentioned on this page may no longer be available, the information about these products remains available to those who may need it.
Be sure to mention the model number in the Comments field of the Ordering Form when ordering upgrade modules from MacGurus.



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