Radio Shack

This reference manual gives the technician all the information that's needed to troubleshoot and repair a TRS-80 Model I Micro Computer. Block drawings, detailed waveforms, and complete schematic diagrams are provided on fold-out pages. Actually, the schematic diagrams are printed on two, large, 35x11-inch fold-outs.

Considerable space is given to the theory of operation: CPU address lines, CPU data bus, CPU control group, system RAM, video divider chain, video RAMs, video processing, keyboard, input and output port, system power supply and Level II ROMs.

The chapter on troubleshooting aids the technician with the disassembly of the computer keyboard where the logic board and CPU are located. An exploded view makes it easy to take things apart and put them back together again.

A troubleshooting flowchart enables the technician to quickly isolate which one of 21 sections contains the probable cause of a problem. There is a separate flowchart to help the technician with CPU troubleshooting. There are also helps for troubleshooting ROM, RAM, address decoder, sync generator, power supply, ports, cassette tape recorder/player, and video display monitor. In fact, every item discussed in the previous chapter about the theory of operation is discussed again from a troubleshooting perspective in this chapter.

In the back of the manual, there is a complete parts list keyed by symbols to the schematic diagrams. There are multiple tables with line-item descriptions and part numbers for capacitors, diodes, jacks, relays, transistors, resistors, switches, sinks, sockets, crystals, integrated circuits, RAM kits, and main printed circuit board.… (mehr)

DeskMate Version 1.0 came packaged with each purchase of a Tandy 1000 PC in 1984. For instance, there was (1) DeskMate diskette (a 360K 5.25" floppy disk), (2) DeskMate: A Reference Manual, (3) DeskMate: A Quick Reference Guide, and this (4) Introduction to the Tandy 1000: A Tutorial to DeskMate.

DeskMate provided a CGA windows environment long before the earliest version of Microsoft Windows made its appearance in the marketplace. DeskMate was an integrated software program, not an operating system.

Its features included Main Menu, Text, Filer, Worksheet, Calendar, Alarm, Telecom, Phone, Mail, and Host.… (mehr)

DeskMate Version 1.0 came packaged with each purchase of a Tandy 1000 PC in 1984. For instance, there was (1) a DeskMate diskette (a 360K 5.25" floppy disk), (2) an Introduction to the Tandy 1000: A Tutorial to DeskMate, (3) a DeskMate: A Quick Reference Guide, and (4) this handy guide, DeskMate: A Reference Manual.

DeskMate provided a CGA windows-like environment long before the earliest version of Microsoft Windows made its appearance in the marketplace. DeskMate was an integrated software program, not an operating system.

Its features included Main Menu (a pull-down menu), Text (a word processor), Filer (a database manager), Worksheet (a spreadsheet program), Calendar (time management software), Telecom (a communications terminal), Alarm (audible reminder of scheduled events), Phone (used to store, view, and place calls), Mail (a messaging system), and Host (allowed remote access by modem).

The Tandy 1000 was the successor to Radio Shack's TRS-80 line of computers.

These early Tandy 1000 computers had MS-DOS 2.11 built into ROM allowing the OS to boot in a few seconds.

An odd feature of the Tandy 1000 was a non-standard edge card printer connector built onto the motherboard and protruding through the rear. An adapter was needed for the T-1000 to work with a standard IBM-style printer.

The Tandy 1000 also featured a proprietary keyboard and keyboard port.

DeskMate augmented normal PC activities with its pull-down menus and interactive dialog boxes, thus simplifying many DOS operations.

Today we would call DeskMate a DOS shell and a graphical user interface (GUI). Although you could use a mouse with DeskMate, it didn't need a mouse to operate.

The hardware demands of DeskMate were minimal. It ran just fine on a Tandy 1000 with 128K RAM and one 360K 5.25" floppy disk drive. DeskMate was written in C and Assembly Language.… (mehr)