Tandy 1000A Service Manual Supplement

Tandy's Supplement to the Tandy 1000 Service Manual covers the Tandy 1000A main logic board and is copyright 1985 Tandy Corporation. It is meant to be used with the original Tandy 1000 Service Manual (25-1000), described on Tandy 1000 Documentation. The hosted scan, from the Internet Archive, has 51 pages.

Contents

Sections and printed page numbers:

• 1, Introduction: the 1000A board as a cost reduction of the original, with a two-layer board, 73 ICs and three new custom chips, and the user-visible changes (p. 1)
• 2, Custom circuits: the Custom Address Array, the Custom Timing Generator Array and the Custom Keyboard I/F Array, with pin-outs, block and timing diagrams (pp. 3 to 14)
• 3, Parts list: main assembly, main logic board, optional parts (the 8087) and the parts added for the international version (pp. 15 to 22)
• 4, Component layout of board 8709604 revision B (p. 23)
• 5, Schematics: copies of the original 1000's schematic 8000226 marked with the logic each custom chip replaces, followed by the 1000A board's sheets (from p. 27)

What this supplement does not contain

There are no disassembly, adjustment, power supply or troubleshooting sections; those are in the original manual, since the 1000A uses the same 54 W supply and chassis parts.

Notes on the text

• The Custom Address Array is part 8079010 in the text and 8079013 in the parts list.
• CR2 is listed as "Zener Diode 1N4148 75V"; check the part fitted against the schematic.
• The DRAM list includes U44, but the socket list does not.

Pages that cite this document

• Tandy 1000A: the changes from the original board, specifications
• Tandy 1000A General Maintenance: sockets, parts list notes, sound
• Tandy 1000A Troubleshooting Guide: timing generator pins, memory, sound
• Tandy 1000A Capacitor Replacement Guide: the main board capacitor list

Download: Tandy 1000A Service Manual Supplement (1985).pdf