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Tandy 1400 LT Service Manual

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Tandy's Tandy 1400LT Laptop Computer Service Manual covers the Tandy 1400 LT, catalogue number 25-3500, and is copyright 1988 Tandy Corporation. The hosted copy, from TVDog's Tandy 1000 archive, has 301 pages and a text layer.

Contents

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Parts and printed page numbers from the manual's contents list:

  • I, Introduction: system overview, external and internal views with photographs of the main, power, LCD and memory boards, hardware specifications (pp. 1-1 to 1-9)
  • II, Disassembly instructions: top case, battery and rear covers, LCD frame and LCD, LED PCB and keyboard, battery pack, base frame, floppy drives, power source PCB and its box, cables, contrast knob, speaker, main PCB, pedestals, handle and bottom case (pp. 2-1 to 2-15)
  • III, Preventive maintenance: cleaning, real-time clock frequency adjustment with trimmer C51, LCD controller frequency adjustment with trimmer C32 (p. 3-1)
  • IV, Theory of operation: CPU, clock generator, memory map and memory card, ROM and I/O maps, interrupts, keyboard and external keyboard, floppy drives and DMA, printer, LCD controller and video outputs, serial interface, real-time clock, speaker, power supply and battery warnings, expansion bus and internal modem connector (pp. 4-1 to 4-70)
  • V, Troubleshooting: flowcharts from a dead machine through the DC/DC converter, memory, LCD, backlight, keyboards, buzzer, clock, printer, internal and external drives, serial port, monitor outputs and indicator LEDs (pp. 5-1 to 5-33)
  • VI, Exploded views and parts lists for the main, power, sub, memory and LED boards, the LCD unit, the floppy drive, the mechanical parts and the keyboard (pp. 6-1 to 6-31)
  • VII, Circuit diagrams for the main PCB, the RAM PCB, the LED PCB and the power and sub PCBs (pp. 7-1 to 7-20); VIII, PCB views (pp. 8-1 to 8-5)
  • Appendices: A, LCD specifications; B, replacement of the EL backlight; C, 3.5-inch floppy drive specifications; D, floppy drive maintenance, with fault diagnosis, parts replacement and head alignment; E, character code table; F, description of I/O commands

Notes on the text

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The manual gives two input ranges for the AC adapter: 8-20 V in the power source notes, and 13.5 V minimum to 20 V maximum in the power supply section, which the troubleshooting chart's 15-20 V agrees with. The manual is for the 1400 LT, 25-3500, and does not mention the later 1400 FD and 1400 HD.

Pages that cite this document

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Download: Tandy 1400 LT Service Manual (25-3500, 1988).pdf


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