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IBM PS2 Model 55 Technical Reference (October 1990)

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The IBM Personal System/2 Model 55 Technical Reference is IBM's 64-page model-specific interface reference for the PS/2 Model 55 SX (8555), Second Edition, October 1990 (copyright 1989, 1990). It covers the Type 1 and Type 2 system boards, both 16 MHz, identified by model byte F8 and submodel 0C (Type 1) or 1E (Type 2); the Type 2 board has additional memory for configuration information (Figure 1-1, p. 1-3). The preface says it is to be used with the Hardware Interface Technical Reference volumes Architectures and Common Interfaces and the PS/2 and PC BIOS Interface Technical Reference. Vertical bars mark changes from the February 1989 first edition.

Contents

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From the contents page (p. vii):

  • Section 1, System Overview (p. 1-1): description and model bytes, system board features, I/O address map, specifications (physical, Figure 1-5, p. 1-7; acoustics p. 1-8), and a power supply section added in this edition (pp. 1-9 to 1-10).
  • Section 2, Programmable Option Select (p. 2-1): system board POS address map, card selected feedback, enable/setup (hex 0094), POS registers 2 to 5 (hex 0102-0105) and adapter setup.
  • Section 3, System Board (p. 3-1): microprocessor and coprocessor, Micro Channel implementation and exception reporting, central arbiter, bus adapter, diskette drive controller, ROM and RAM with error recovery, memory map and connectors, RT/CMOS RAM (p. 3-13), system control ports and power-on password.

What this manual does not contain

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It is a programming and interface reference: no FRU numbers, removal procedures, symptom index, schematics or component values.

What it settles

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From the power supply section (pp. 1-9 to 1-10):

  • The system-board voltages are +5, +12 and −12 V; the drives receive +5 and +12 V.
  • Maximum currents (Figure 1-7): internal fixed disk drive 0.8 A at +12 V and 0.8 A at +5 V per supply connector; auxiliary device 300 mA and keyboard 275 mA at +5 V.
  • Each channel connector may draw 1.6 A at +5 V, 0.175 A at +12 V and 0.040 A at −12 V (Figure 1-8).
  • A short on any output, or an internal overvoltage before any output exceeds 130 % of nominal, latches all outputs off until the fault is removed and the power switch has been off for at least ten seconds. The outputs track within 50 ms of each other at power-on.

The physical specifications (Figure 1-5) give 8.64 kg with drives, heat output 140 W (480 BTU/hour), a switch-selected input of 90-137 V or 180-265 V, and 0.08-0.24 kVA input.

Pages that cite this document

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Download: IBM PS2 Model 55 Technical Reference Oct90.pdf

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