Radio Shack TRS-80 Model 100 User manual

.
MODEL I OO
PORTABLE COMPUTER
Catalog Numbers 26-3801/3802
CUSTOM MANUFACTURED FOR RADIO SHACK H A DIVISION OF TANDY CORPORATION
Radio /hack
Service Mmm iD
26
-
3801/3802

TABLE OF CONTENTS
PAGE
NUMBER
I. INTRODUCTION
GENERAL.
SPECIFICATIONS.
CONNECTORS, SWITCHS AND CONTRAST VR
II. disassembly/reassembly
DISASSEMBLY.
REASSEMBLY .
Ill PREVENTIVE MAINTENANCE
ADJUSTMENT OF THE TRS-80 Model 100.
CLEANING OF THE DOBY AND LCD DISPLAY-
MODEM TRANSMITTING LEVEL ADJUSTMENT . ..
IV. THEORY OF OPERATION
GENERAL.
CPU (MSM80C85ARS) .
MEMORY .
ADDRESS DECODING AND BANK SELECTION .. .
MEMORY MAP.
I/O MAP AND I/O PORT DESCRIPTION.
KEYBOARD .
CASSETTE INTERFACE CIRCUIT .
PRINTER INTERFACE CIRCUIT.
BARCODE READER INTERFACE CIRCUIT.
BUZZER CONTROL CIRCUIT.
SYSTEM BUS .
LCD INTERFACE CIRCUIT.
CLOCK CONTROL CIRCUIT.
SERIAL INTERFACE CIRCUIT.
LIQUID CRYSTAL DISPLAY.
POWER SUPPLY AND AUTO POWER OFF CIRCUIT
RESET CIRCUIT.
V. TROUBLE SHOOTING
HOW TO MAKE USE OF THIS SECTION.
TROUBLE SHOOTING GUIDE.
CHECK LIST.
VI. EXPLODED VIEW AND PARTS LIST
EXPLODED VIEW.
PARTS LIST .
VII. DIAGRAMS
SCHEMATIC DIAGRAM.
P.C.B. VIEW.
1- 3
1- 4
1 - 6
2 - 1
2 - 2
3- 1
3- 1
3- 1
4- 1
4- 2
4- 2
4- 3
4- 6
4- 7
4- 8
4- 9
4-10
4-11
4-11
4-12
4-13
4-15
4-17
4-26
.4-32
.4-34
5- 1
5- 2
5-12
6 - 1
6- 3
7- 1
7- 3

appendix a/ installation OF OPTIONAL RAMs AND ROM
appendix b/character code table .
APPENDIX C/ LSI DESCRIPTION
MSM80C85ARS (CPU)
MSM81C55RS (PIO) . C ' 1
IM6402 (UART) C11
MPD1990AC (TIMER) ... . 015
MC14412 (MODEM) .. C-19
TC5518BF-25 (RAM) ... C ' 24
LH-535618 (ROM) C-28
. C-31

FIGURE
NUMBER
DESCRIPTION
PAGE
NUMBER
1-1
1-2
2-1
4-1
4-2
4-3
4-4
4-5
4-6
4-7
4-8
4-9
4-10
4-11
4-12
4-13
4-14
4-15
4-16
4-17
4-18
4-19
4-20
4-21
4-22
4-23
4-24
4-25
4-26
4-27
4-28
4-29
4-30
4-31
4-32
4-33
4-34
4-35
4-36
4-37
4-38
6-1
6-2
7-1
7-2
7-3
7-4
7-5
7-6
Front View.
Keyboard Layout.
Disassembly Procedure.
System Block Diagram.
Internal Wiring Diagram of RAM Pack
Address Decoding for RAM Chip.
Standard and Optional ROM Selection ....
Memory Map.
I/O Address Decoder.
Condition of Pressing “T" Key.
Modulation Circuit of Cassette Interface ..
Demodulation Circuit of Cassette Interface
Remote Circuit of Cassette Interface.
Printer Interface Circuit.
Bar Code Reader Interface Circuit.
Buzzer Control Circuit.
LCD Interface Circuit.
LCD Interface Timing Chart.
Data Input Condition of mPD1990AC ....
Time Set Condition of /uPD1990AC.
Time Read Condition of /iPD1990AC.
Data Output Condition of /iPD1990AC
Control Register Load Condition of IM6402
Status Read Condition of IM6402 .
Data Transmission Condition of IM6402 . ..
Data Reception Condition of IM6402 .
MODEM/RS-232C Exchange Circuit.
RS-232C Interface Circuit.
MODEM LSI and Peripheral Circuit.
Transmission Filter Circuit.
Reception Filter and Comparator Circuit ...
MODEM Connector Interface Circuit.
Construction of LCD Panel .
Operation Theory of LCD Panel.
LCD Electrodes.
LCD View Angle .
HD44103 Internal Block Diagram.
HD44102 Internal Logic Diagram .
LCD Waveform.
Power Supply and Reset Circuit.
Oscillation Waveform.
Exploded View.
Bottom View.
MAIN P.C.B.-Schematic Diagram.
LCD P.C.B.-Schematic Diagram.
MAIN P.C.B.
MAINP.C.B.
LCD P.C.B. . . . . ! . ! .
LCD P.C.B.
. 1 - 1
. 1 - 2
. 2- 1
.4- 1
.4- 3
.4- 4
.4- 5
. 4- 6
. 4- 7
. 4- 8
. 4- 9
.4- 9
. 4-10
. 4-10
.4-11
. 4-12
.4-13
. 4-14
.4-15
.4-16
. 4-16
.4-17
.4-18
.4-19
. 4-19
. 4-20
.4-21
.4-22
.4-23
, 4-24
4-24
4-25
4-26
4-27
4-28
4-28
4-29
4-30
4-31
4-33
4-33
6- 1
6 - 2
7- 1
7- 2
7- 3
7- 4
7- 5
7- 5

. A- 1
A-1
C-1
C 9
80C85 Functional Block Diagram.
. C- 1
. C- 1
U‘4
. C- 6
. C- 8
0-4
. C- 8
0-0
n a
. C-9
r 7
. C-10
. C-10
O-o
C-9
81C55 Pin Configuration and Block Diagram ...
. C-11
. C-13
O-1 u
. C-14
o -1 i
. C-14
O-1 z
C-13
81C55 Timer Output Waveform Countdown from 5 to 1 .
. C-15
. C-15
O- 14
. C-16
0-1 O
. C-20
O* ID
. C-21
O- 1 /
C-18
C-19
A/PD1990AC Command Input Timing Diagram.
/iPDI 990AC Data Input/Output Timing Diagram.
. C-22
. C-23
. C-26
O-ZU
. C-26
. C-26
. C-27
w"Zo
TPRR1 RRF-9R Pin 1 avnut ..
. C-28
r ok
. C-29
U“Z J
. C-29
u'Zu
. C-30
o-z /
. C-31
. C-32
C-30
LH-53518 Timing Diagram.
. C-32
TABLE
NUMBER
DESCRIPTION
PAGE
NUMBER
I/O Man .
.4- 7
.4-8
4-Z
.4-12
.4-13
4-4
.4-21
4-0
.4-22
4-D
C-1
80C85 Interrupt Priority, Restart Address and Sensitivity .
. C- 5
. C-7
u-z
.. C-7
U-o
. C- 8
0-4
. C-15
v‘0
. C-28
0-0
C-7
LH-535618 Pin Assignment.
. C-31

SECTION I
INTRODUCTION

FRONT VIEW
1-1

INTRODUCTION
GENERAL
This manual is prepared for the TRS-80 Model 100 technicians working in field or in repair centers.
The user of this manual should be acquainted with Z-80 and 80C85 (8085) microprocessors and also with
81C55 PIO and IM6402 UART LSIs.
Detailed technical information for those microprocessors and LSIs is provided in APPENDIX C of this
manual.
This manual consists of seven sections and three appendices:
• Section I
This section gives general information on the TRS-80 Model 100 such as specifications, switch functions
connectors and special features.
• Section 11
This section describes the disassembly and reassembly procedures.
• Section III
This section describes preventive maintenance and adjustment of the TRS-80 Model 100.
• Section IV
This section describes general theory of the TRS-80 Model 100 operation, including operational theory
of main P.C. Board assembly, LCD Board assembly and keyboard assembly.
• Section V
This section describes how to troubleshoot the TRS-80 Model 100.
• Section VI
This section provides a part list and an exploded view of the TRS-80 Model 100.
• Section VII
This section provides schematics, P.C. Board diagrams and silk screen views of P.C. Boards of the TRS-80
Model 100.
• Appendix A provides instructions for installing the optional ROM and additional RAMs.
• Appendix B provides character code chart of the Model 100.
• Appendix C provides technical information of microprocessors and UART LSIs.
The Model 100, a portable computer that fits easily into a regular sized briefcase, has many special features
and functions for home and business use.
Its five built-in Application Programs offer various uses:
• BASIC
BASIC lets you write and run your own programs.
Also, BASIC provides various mathematic functions (as described in PART-1 II of owner's manual).
• TEXT
TEXT Lets you create new files containing memos, documents or text of any kind.
• ADDRSS
ADDRSS lets you get information such as addresses and telephone numbers from the ADRS file.
• SCHEDL
SCHEDL lets you get information concerning appointments, meetings, etc., from the NOTE file.
• TELCOM
TELCOM lets you use the TRS-80 Model 100 as an auto-dialer or for computer-to-computer communi¬
cations.
1-3

In addition to Application Programs, you can connect the following peripherals to the Model 100:
• Cassette recorder to store programs or data on cassette tape.
• Printer to print copies of documents, programs or data.
• Bar code reader to identify the product marking codes of various marchandises. (Optional/extra soft¬
ware required.)
• Communication interface to transfer/receive data to/from the Model 100 and another computer (Acous¬
tic Coupler or Modem Cable required).
SPECIFICATIONS
(1) Main Components
(a) Keyboard
71 keys (9x8 matrix)
• Alphabet keys .
• Number keys.
• Picture-control keys .
• Function keys .
• Special symbol keys .
• Mode keys ....
• Other special-use keys
(b) LCD display
• Display panel.
27
10
7
8
8
5
6
240 x 64 Full-dot matrix
(c)
(d)
(e)
1/32 Duty
1/6.66 Bias
• Dot pitch.0.8 x 0.8 mm
• Dot size . 0.73 x 0.73 mm
• Effective display area.191.2x50.4 mm
Operation batteries
• Batteries.... Four type AA Alkaline-manganese batteries
• Operation time. Five days (At four hours/day)
Twenty days (At one hour/day)
(Note: With I/O disconnected)
Memory protection battery (On main P.C.B.)
• Battery. Rechargeable battery
• Protection time .About 40 days (8 KB)
About 10 days (32 KB)
• Recharge method.Trickle charge by AC adapter or operation batteries
LSIs
• CPU.80C85
Code and pin compatible with 8085
• ROM .Maximum 64 KB (2 Banks of 32 KB)
Standard 32 KB
Option 32 KB
1-4