Radio Shack TRS-80 III User Manual

FIGURE
NUMBER
LIST OF ILLUSTRATIONS (Cont'd)
TITLE
SECTION V - RS-232C CIRCU IT BOARD
PAGE
NUMBER
1
2
2
3
1
2
3
4
1
2
3
1
2
3
4
5
1
1A
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
18
19
20
20
RS-232C Board to CPU Board Signal Description . . . . . . . . . . . . . .. 59
RS-232C
PC Board - Component Side -. . . . . 60
RS-232C
PC Board - Circuit Side . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 61
Model III RS-232C Schematic Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . 63
SECTION
VI- POWER SUPPLY
Test Set-Up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 67
02 Collector Waveform .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 68
02 Base Waveform . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 68
Power Supply Schematic Diagram
71
SECTION VII - VIDEO MONITOR
Video Monitor Printed Circuit Board 76
Deflection Yoke Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 77
Video
Monitor Assembly Schematic Diagram. . . . . . . . . . . . . . . . . . . . .. 78
SECTION
VIII - ILLUSTRATED PARTS CATALOG
Outer Case Assembly " 81
Case Top Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 82
Base Plate Assembly . . . . . . . . . . . . . . . . . . . . .. 83
Metal Chassis Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 84
Disk Drive Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 85
SECTION IX - FLOPPY DISK DRIVE
PC Board Component Locations (Logic Board) 94
PC Board Components Locations (Servo Boards) 95
Resistor
Termination. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 96
Cable Assembly - Connector Pin Removal Chart 96
Functional Block Diagram 98
FM Recording . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 98
Write Timing Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 100
Read Timing Diagram 100
Interface Configuration ,
101
Logic Board Test Points and Connector Locations 106
Servo Board Connector Locations ... . . . . . . . . . . . . . . . . . . . . . . . . .. 107
"Cat's Eyes" Pattern . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 109
Radial Adjustment
.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 109
Track
00 Stop Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 110
Index Sector Timing
.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 110
Index Adjustment , 110
Upper Arm
and Carriage 111
Illustrated Parts Catalog - Exploded View 118
Mini-Disk Drive Schematic (Sheet
1) 120
Mini-Disk Drive Schematic (Sheet
2) 121
Servo Board Schematic 122
Mini-Disk Drive Schematic (new board) . . . . . . . . . . . . . . . . . . . . . . . . . 123
Mini-Disk Drive Schematic (new board) " 124

Radio Shack TRS-80 III Specifications

General

Brand	Radio Shack
Model	TRS-80 III
Category	Desktop
Language	English