Jump to content

TRS-80 PC-1 Documentation

From RetroTechCollection

The TRS-80 Pocket Computer and Cassette Interface Service Manual is Radio Shack's service manual for the TRS-80 Pocket Computer (catalogue number 26-3501, later called the PC-1) and the 26-3503 cassette interface. The cover says the units were custom manufactured for Radio Shack, a division of Tandy Corporation; the computer is a Sharp PC-1211. The scan has 40 pages and no text layer.

Contents

[edit | edit source]

Section and printed page numbers, from the manual's table of contents:

  • 1. Specifications (p. 1): keyboard, display, functions, programming language, power supply (four MR44 cells) and general data (pp. 1-2)
  • 2. Block diagram (p. 3): block diagram, CPU I and CPU II, RAM organisation, display operation and timing, and the power supply with the LCD voltage adjustment (p. 9)
  • 3. LSI signal descriptions (p. 10): pin tables for CPU I, CPU II and the display chip, and IC pin-outs (pp. 10-13)
  • 4. Before servicing (p. 14): disassembly, repair procedure, LSI replacement and current consumption
  • 5. Cassette tape and interface (p. 14): recorder requirements
  • 6. Cassette operation (p. 15): recording format and method, remote control, testing and repairing the cassette interface, relay control waveforms (pp. 15-21)
  • 7. Check program (p. 22)
  • 8. Circuit diagrams and board layouts (p. 23): operation circuit diagram (p. 23), operation PCB (p. 24), key circuit (p. 25), key PCB (p. 26), 26-3503 circuit diagram and PCB (p. 27)
  • 9. Parts list for 26-3501 (pp. 28-30), with the exploded view on p. 31
  • 10. Parts list for 26-3503 (pp. 32-33), with the exploded view on p. 34

The parts lists give Radio Shack and Sharp part numbers for each item.

What this manual does not contain

[edit | edit source]
  • It does not cover the later 26-3505 printer and cassette interface.
  • There is no fault-finding chart for the computer itself. The check program and the cassette tests show whether a unit works; beyond that the manual gives signal descriptions, schematics and parts lists.
  • The parts lists give values and part numbers but no circuit references.
  • The scanned check program table is cut off on the right at display column 20.
  • The computer's electrolytic capacitor is listed as 100 µF 10 V. Sharp's PC-1211 service manual lists the same Sharp part number as 1 µF 50 V.
  • Printed page numbers run two lower than the PDF page numbers up to p. 22. After that the gap widens, because some drawings span two scanned pages and p. 29 was scanned twice; p. 34 is PDF page 40.

Pages that cite this document

[edit | edit source]

Download: Radio Shack TRS-80 Pocket Computer and Cassette Interface Service Manual (26-3501, 26-3503).pdf

Retrieved from "https://retrotechwiki.com/index.php?title=TRS-80_PC-1_Documentation&oldid=28966"