Tandy 1000 Technical Reference Manual

Tandy 1000
4-4-5. Check and Adjustment of Disk Rotation Speed
Technical Reference Manual
This item is only applied to the FDD which has a DD motor Ass'y with
the variable resistor Rl for adjusting the rotational speed of the
disk on the PCBA DD motor servo. Refer to Fig.3ll as to the mounting
position of the variable resistor RI.
For the DD motor Ass'y without the variable resistor, the rotation
speed is fixed by the ceramic oscillator in the servo circuit and no
adjustment is required.
(A) Equipment
(1) Common screwdriver, small size
(2) SKA or user's system
(3) Frequency counter (not required when the SKA is used)
(4) Work disk (soft sectored)
(B) Check and adjustment procedure
(1) General method
(a) Connect the frequency counter to TP4 (Index) of the PCBA MFD control
or to the INDEX interface signal line.
(b) Start the spindle motor and install a work disk.
(c) Set the head to track 00.
(d) Confirm that the pulse interval at TP4 is ~ithin the following range.
TP4 pulse interval: 200±3msec
(e) If the value in item (d) is out of the specified range, adjust the
variable resistor RI on the rCBA DD motor servo to obtain the median
value in the specified range in item (d).
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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