IBM PC 5150 Technical Reference

The IBM Personal Computer Technical Reference (Hardware Reference Library), Revised Edition, April 1984, IBM part number 6322507, is the 309-page technical reference for the IBM PC 5150. © IBM 1981, 1982, 1983, 1984.

This is one of the small number of documents on this wiki for which IBM did publish component-level drawings: Section 1 ends with logic diagrams of the system board, printed as a ten-sheet set for the 64–256 KB planar.

What it contains

Section 1, System Board (1-1) — the 8088, data flow diagrams, the system memory map, timers, interrupts, ROM, RAM and DMA; the I/O channel with its diagram, signal descriptions and address map (1-14 to 1-24); other circuits including the speaker circuit (1-25) and the cassette interface with block diagrams (1-27); the 8255A I/O bit map (1-31); the system-board switch settings (1-33); specifications and card specifications (1-34); and the logic diagrams (1-36).
Section 2, Coprocessor — the 8087, its programming and hardware interface, and the data-type table.
Section 3, Power Supply (3-1) — input requirements, the Vdc and Vac outputs, overvoltage/overcurrent protection on both primary and secondary sides, the power good signal, and the power supply connectors with pin assignments.
Section 4, Keyboard — block diagram, keyboard diagrams, connector specifications and the keyboard logic diagram (4-13).
Section 5, System BIOS — usage, keyboard encoding, the BIOS cassette logic and the full System BIOS assembler listing (5-29).
Section 6, Instruction Set; Section 7, Characters, Keystrokes and Colors; Section 8, Communications.

What it does not contain

Not a service manual: no FRU part numbers, no removal and replacement procedures, no symptom-to-FRU index and no fault trees. The logic diagrams show the board as designed; they are not a silkscreen map, and there is no bill of materials, so a capacitor's designator has to be matched to the board by hand.

It documents the 64–256 KB planar as its primary subject; the earlier 16–64 KB board is covered by earlier editions of the same book.

What it settles

The 5150 power supply. Four DC outputs: +5.0 Vdc 2.3–7.0 A at +5 % / −4 %; −5.0 Vdc 0.0–0.3 A at +10 % / −8 %; +12.0 Vdc 0.4–2.0 A at +5 % / −4 %; −12.0 Vdc 0.0–0.25 A at +10 % / −9 %.

It also documents something easily forgotten: the 5150 supply has a filtered, fused AC output switched by the main power switch, with a maximum of 0.75 A at the rear receptacle. That is the socket the monitor plugged into, and it is live logic, not a pass-through.

Download it here: IBM PC 5150 Technical Reference.pdf

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