Tandy 1000 Technical Reference Manual

Tandy 1000 Technical Reference Manual
Items Timing
2F
interval
4lJs, Nom.
4/3F interval
6lJs, Nom.
IF
interval
8lJs,
Nom.
Pulse width
l±0.5lJs
(Table 304) Read data pulse timing
(6) TP6 (File protect sensor)
Test point to observe the output of the file protect detection
photo-transistor (shumitt inverter included) .
As well as the WRITE PROTECT output signal, TP6 becomes LOW level
when a disk with the masked write protect notch (write operation cannot
be done) is installed.
TP6(File protect sensor)
Notch ope~
(TTL level)
~ Notch masked
(Fig.3l8) Typical waveform of TP6
(7) TP7, TP8 (Pre-amplifier)
Test point to observe the read pre-amplifier output signals.
The pre-amplifier has two outputs of the- order of several dozen to
several hundred mVp-p, and they differ in phase by 180· (opposite phase) •
Both outputs are observed at TP7 and TP8 respectively.
For an accurate observation of the read waveforms, use two channels of
an oscilloscope with one channel set to Invert mode and Add mode of
both channels. Use G (OV) test point for the oscilloscope ground.
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Tandy 1000 Specifications

General

Processor	Intel 8088
Processor Speed	4.77 MHz
RAM	128 KB (expandable to 640 KB)
Operating System	MS-DOS 2.11
Manufacturer	Tandy Corporation
Release Year	1984
Storage	Single or double 5.25" floppy disk drive (360 KB), optional hard drive
Sound	Tandy 3-voice sound
Ports	Parallel, Serial
Graphics	CGA (Color Graphics Adapter)
Graphics Modes	320x200, 640x200