Radio Shack 26-3801 User manual

Radio /haeti
Service
®
MODEL 100
MICROCOMPUTER
26-3801
PRELIMINARY
PRODUCT
INFORMATION
•-
0220 TECHNICAL SUPPORT SERVICES

/
MODEL-100
SERVICE MANUAL
#0220 TECHNICAL SUPPORT
DOCUMENTATION LIBRARY

3
TABLE OF CONTENTS
SECTION
NUMBER
IINTRODUCTION
SYSTEM OVER VIEW
1. Specification
2. Switches and Connecters
3. Key Layout
4. LCD character Font
II DISASSEMBLY/REASSEMBLY
1. Disassembly
2. Reassembly
III MAIN P.W. BOARD TECHNICAL DESCRIPTION
1. LSIs
2. Memory
3. Address Decoding and Bank Description
4. Memory Map
5. I/O Map and I/O Port Description
6. Keyboard
7. cassette Interface Circuit
8. Printer Interface Circiut
9Bar Code Reader Interface Circuit
10. Buzzwe Control Circuit
11. System Bus
12. LCD Interface Circuit
13. Clock Circuit
14. Serial Interface Circuit
15. Power Supply and Auto Power Off Circuit
16. Reset Circuit
MAIN P.W. BOARD PARTS LIST
IV LCD P.W. BOARD TECHNICAL DESCRIPTION
1. LCD Pannel
2. LCD Contrl Circuit
3. LCD Waveform
LCD P.W. BOARD PARTS LIST
VILLUSTRATION PARTS CATALOG
ILLUSTRATION PARTS LIST

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VI TROUBLE SHOOTING
1. Trouble Shooting Guide
2.Chevking Procedure
3. Check List
VII PRINED WIRING BOARD
MAIN P. W. BOARD
LCD P. W. BOARD

£
CONFIDENTIAL
SECTION 1
INTRODUCTION

S"
System Overview
i. Specifications
(1) Main Components
(a) Keyboard
71 keys (9x8 matrix)
Alphabet keys 2 7
Number keys 10
Picture-control keys 7
Function keys 8
Special symbol keys 8
Mode keys 5
Other special-use keys ...... 6
LCD display
Display Panel ...240 x 64 Full-Dot matrix
1/32 duty
1/6.66 bias
Dot Pitch 0.8x0.8mm
Dot Size 0.73 x0.73 mm
Effective Display Area ...191.2 x50.4 mm
(b)
(c)
(d)
Case
Dimensions .... 300
Material ,... . ABS
Operation Batteries
Batteries ....
(W) x 46.5 (L) x215 (H) mm
Operation time
(e)
.Four alkali-manganese batteries
(AM-3)
.5days (at 4hours/day)
20 days (at 1hour/day)
(note: with I/O disconnected)
Memory Protection Battery (on main PWB)
Battery ....
Protection time
Recharere method
Rechargeable Battery (3-51FT)
About 40 days (8 KB)
About 10 days (32 KB)
Trickle charge by AC adaptor,
or operation batteries

(f) LSIs
CPU ...80C35 (OKi)
Code and pin compatible with 8085
ROM . . .Max. 64 KB (2 Banks of 32 KB)
STANDARD 32 KB
OPTION 32 KB
RAM .. . Max. 32 KB
STANDARD 8KB (four TC5518BF (TOSHIBA))
RAM PACK
incremental 8KB RAM PACK on PWB
CLOCK/CALENDAR .. . yPD 1990AC (NEC)
No leap year/No February 29
(2) I/O Interface
(a) RS-232C
Conforms to EIA standards
Signal . . . TXR (Transmit Data)
RXR (Receive Data)
RTSR (Request To Send)
CTSR (Clear To Send)
DSRR (Data Set Ready)
DTRR (Data Terminal Ready)
Programmable Items
*Data Length ...6, 7or 8bits
*Parity NON, EVEN or ODD
*Stop Bit Length ..1or 2bits
*Baud Rate .... 75, 110, 300, 600, 1200, 2400,4800,
9600, 19200 BPS
Maximum Transmission Distance ... 5m
Driver maximum voltage output
Driver minimum voltage output
Receiver maximum voltage input
Receiver minimum voltage input
±5V
±3.5V
±18V
±3V

7
(b) Modem/Coupler
Conforms to BEL103 standards
Baud Rate ...300 BPS
Programmable Items
*Date Length ...6,7or 8bits
*Parity NON EVEN or ODD
*Stop bit .... 1or 2bits
Full Duplex Answer mode /Call mode,
switchable
Other Functions .. . Hang Up Function
Auto Dialer Function
(C) Audio Cassette Interface
Data Rate ...1,500 BPS
(MARK: 2,400 Hz, SPACE: 1,200 Hz)
(d) Printer Interface
Conforms to Centronics Interface standards
Handshake Signal ...STROBE, BUSY, SELECT
(3.) Special functions
(a) Automatic power OFF
When there is no program operation (awaiting command)
for ten minutes, the power is automatically cut off.
If the PPC is started once again, the power switch is to
be switched OFF and then ON, thus releasing the
automatic power OFF condition.
The display will remain the same as before the power was
cut off.

V
2. Connectors ,Switches and Contrast Volume
(1) Connectors
RS-232C 25 pins (DB-25S)
Printer 26 pins (FRC2-C26-L13-ON)
Modem 8pins (TCS-4490)
Cassette 8pins (TCS-4480)
Bar Code Reader 9pins (A-7224)
System Bus 40 pins (IC Socket)
AC Adaptor s.S<P (Center Minus)
C2) Switches
(a) Power Switch
This is the PPC system power switch.
OKJ IflD OFF ON ED OFF
Power OFF Power ON
Fig. 1
(b) ANS/CALL selector
This switch is used to select the MODEM ANSWER mode or
CALL mode.
ams j(HDioRiq- AWS ED 0RI6-
Call mode Answer mode
Fig. 2
(C) Coupler/telephone selector
This switch is used to select COUPLER (acoustic coupler
connection) or TELEPHONE (direct connection)
.
DfR MAcp DIR ED acp
COUPLER (ACOUSTIC TELEPHONE (DIRECT TELEPHONE
COUPLER CONNECTION) LINE CONNECTION)
Fig. 3