Tandy 1000 Technical Reference Manual

Tandy 1000
Technical Reference Manual
STEP input pulse
TP3(phase B
1 2 3
LJr--------.-Ur------;U,.---
I
magnetized~~ ~
~Phase B magneti,ed
3. 6±0. 3ms
(Fig.3l4) Typical waveform of TP3
PCBA DD motor servo.
The test point is used for the following purposes.
(a) Confirmation and adjustment of the disk rotational speed. Speed
is adjusted by the variable resistor Rl on the PCBA DD motor servo.
(b) Confirmation and adjustment of the index burst timing. Burst timing
is adjusted by the index sensor installation screw in the front OPT
Ass'y
Pulse width
Index
interval
-fl'-- ~nL--------ln!---- (TTL level)
JJ
TP4 (Index)
(Fig.3lS) Typical waveform of TP4 (Speed observation)
Items
Timing
Index
interval
200±4ms
Pulse
width
2 '" S.Sms
Burst
delay
200±200vs
(Table 303) Index timing
... 324 -

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