Sharp CE-121 User Manual

SHARP CORPORATION
CONTENTS
1 . Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3 . LSI signal description 12
4 . About servicing 17
5 . Cassette operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
6. Check program · · · · 25
7 . Circuit diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
8 . PC - 1211 parts list & guide · · 32
9. CE - 121 parts list & guide . . . . . . . . . . . . . . . . . . . . . . · · · · . · · · · · · · · · · · 34
MODEL PC-1211, CE-121
----SHARP----
SERVICE MANUAL

Sharp CE-121 Specifications

General

Brand	Sharp
Model	CE-121
Category	Calculator
Language	English

Summary

1. SPECIFICATIONS

2. BLOCK DIAGRAM

2-1. CPU I, CPU II

Assignments and roles of CPU I and CPU II in the system.

2-2. RAM

Details of RAM configurations and memory mapping.

2-3. Display

2-4. Power source

3. LSI SIGNAL DESCRIPTIONS

4. ABOUT SERVICING

Disassembly procedure

Steps for safely disassembling the unit for servicing.

Repairing procedure

General guidelines for inspecting and repairing internal components.

Replacement of the LSI

Precautions and methods for replacing LSI components.

Measuring current consumption

5. CASSETTE OPERATION

5-1. Recording

Methods and formats for recording data to cassette tape.

5-2. Reproduction

Process for reproducing data from cassette tape.

5-4. Testing the CE121

Procedures for writing and checking test data for CE121.

5-5. About repairing of CE121

7. CIRCUIT DIAGRAM PARTS

7-1. Operation Circuit Diagram

7-2. Operation P.W.B.

7-3. Key Circuit

7-5. CE-121 Circuit Diagram