Wyse WY-30 User manual

WY-30
Maintenance
Manual
For Service Manuals
MAURITRON SERVICES
8Cherry Tree Road, Chlnnor
Oxfordshire, OX9
4QY.
Tel [phone]
Fax [phone]
email:·[email protected]
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OVERVIEW
This maintenance manual contains information on how to service
and repair the WY-30 terminal. We assume you are a qualified
service technician with previous experience in terminal and
computer repair. To take full advantage of this manual, we
suggest you read the information in the order presented.
HOW TO USE THIS MANUAL
This manual is divided into seven chapters and four appendixes.
Chapter one provides important information for the technician who
has never serviced this terminal before. If you are already
familiar with the terminal, the technical information in Appendix
A can remind you about the terminal.
Here is asummary of this manual:
Chapter 1, "General Information," describes the terminal,
including information about internal functions, input/output
(I/O), telecommunications, environmental needs, and operator
controls.
Chapter 2, "Removal and Replacement Procedures," shows you how to
take the terminal apart and put it back together again.
Chapter 3, "Troubleshooting," tells
to fix problems with the terminal.
needed for troubleshooting, a quick
flowchart.
you what to look for and how
It includes a list of tools
reference guide, and a
Chapter 4, "Adjustments and Alignments," describes power supply
and monitor adjustments that control the quality of the display.
Chapter 5, "Illustrated Parts List," includes a list of display
and keyboard assembly parts.
Chapter 6, "Theory of Operation," describes the terminal
operation by function.
Chapter 7, "Schematics," contains schematic representations of
all the terminal's circuits.
iii

Appendix A, "Specifications," lists the terminal's
specifications.
Appendix B, "Connector Pin Assignments," lists the signals on
each pin of the MODEM and the AUX ports located on the rear panel
of the terminal.
Appendix C, "Test Connectors," describes how to make diagnostic
hood test connectors.
Appendix D, "Display Inspection With the Reticle," describes how
to check the terminal's display with a special tool, the reticle.
REFERENCE MANUALS
The following publications provide additional information about
the termina l:
WY-30 User's Guide, Document 880093-01
WY-30 Programmer's Guide, Document 880093-02
iv

TABLE OF CONTENTS
OVERVIEW
...................................................
iii
GENERAL INFORMATION
Introduction 1-2
High Level Functional Description 1-2
Microcomputer 1-2
Memory 1-2
Terminal Control · ··············· 1-2
Input/Output Devices 1-2
Environment 1-4
Operator Interfaces 1-5
Setup Parameters 1-6
Cleaning 1-7
2 REMOVAL AND REPLACEMENT PROCEDURES
Overview 2-2
Before You Start 2-2
Removing and Replacing Assemblies in the
Keyboard Mod ule 2- 3
Removing and Replacing Assemblies in the
Terminal Module 2-5
3 TROUBLESHOOTING
Before You Start 3-2
Troubleshooting Quick Reference Guide 3-3
Troubleshooting Flowchart 3-3
Troubleshooting Aids 3-8
4 ADJUSTMENTS AND ALIGNMENTS
Before You Start 4-2
Power Adjustments 4-3
Does the Terminal Meet the Display Specifications? 4-4
Aligning the Terminal Display 4-6
Adjustments 4-7
v

5 ILLUSTRATED PARTS LIST
Introduction 5-2
Terminal Display Assembly Exploded View 5-3
Keyboard Assembly Exploded View 5-4
Terminal Components List 5-5
Keyboard Components List 5-8
Terminal Board Assembly Layout 5-9
6 THEORY OF OPERATION
Introduction 6-2
Microcomputer and Related Logic 6-2
Power Supply and Monitor Circuitry 6-10
Keyboard 6-13
Communication Ports 6-13
Terms and Abbreviations ········ 6-13
7 SCHEMATICS
Keyboard PCB ·············· 7-3
Terminal PCB (Logic) 7-5
Terminal PCB (Monitor/Power Supply) 7-7
APPENDIXES
A Specifications ··· A-1
B
Connector Pin Assignments B-1
C
Test Connectors C-1
D
Display Inspection with the Reticle D-1
INDEX 1-1
LIST OF FIGURES
1-1 Keyboard ······· 1-3
1-2 Terminal Dimensions 1-4
1-3 Operator Interfaces ·········· 1-5
2-1 Terminal Modules 2-2
2-2
Keyboard Assembly 2-4
2-3 Removing the Terminal Enclosure 2-6
2-4 Replacing the Fuse 2-7
2-5 Removing the Terminal PCB •••.••..••.••.•••...••••••••. 2-9
2-6
Removing the CRT/Yoke Assembly 2-11
2-7 Replacing the Yoke 2-12
2-8 Discharging the Anode Before Removal 2-13
2-9 Discharging the Anode Before Installation 2-14
3-1 Troubleshooting Flowchart 3-4
vi

LIST OF FIGURES Continued
4-1 Power Supply Component Layout 4-3
4-2 Ad j us tmen t Locations 4-8
4-3 Yoke Lock on the CRT Neck 4-10
4-4 Display Magnets ~ 4-11
4-5 Centering Rings 4-12
5-1 Terminal Display Assembly Exploded View 5-3
5-2
Keyboard Assembly Exploded View 5-4
5-3
Terminal Board Assembly Layout 5-9
6-1 Memory Map 6-3
7-1 Keyboard PCB Schematic 7-3
7-2 Terminal PCB Schematic (Logic) 7-5
7-3
Terminal PCB Schematic (Monitor/Power Supply) 7-7
D-1 Video Inspection Reticle D-1
D-2 Checking Width and Height D-3
D-3
Checking Straightness, Pincushioning,
Centering, and Vertical Linearity D-4
LIST OF TABLES
3-1 Troubleshooting Quick Reference Guide 3-3
3-2 Terminal Installation Checklist 3-8
3-3 Power-On Self-Test Error Messages 3-11
3-4 Diagnostic Self-Test Error Messages 3-12
3-5 Terminal PCB Circuit Isolation Jumpers 3-13
4-1 Display Problems and Adjustments 4-7
4-2 Screen Areas Affected by Display Magnets 4-11
5-1 Terminal PCB Components List 5-5
5-2 Keyboard Components List 5-8
5-3 Diagnostic Self-Test Connectors 5-11
6-1 6800 Interrupt Sources 6-3
6-2
Values Loaded into CRTC 6-7
6-3 Screen Attribute Assignments 6-8
B-1 MODEM Port Pin Assignments (DTE) B-1
B-2
AUX Port Pin Assignments (DTE) B-1
vii

1 GENERAL INFORMATION
Introduction
...............................................
1-2
High Level Functional Description 1-2
Microcomputer 1-2
Memory 1-2
Terminal Control 1-2
Input/Output Devices 1-2
CRT Display 1-3
Communications Interfaces 1-3
Keyboard 1-3
Environment
.............................................. ..
1-4
Operator Interfaces 1-5
Keyboard 1-5
P ower Cord 1-6
Communications Cable 1-6
AC Power Switch 1-6
Brigh tness Slideswi tch 1-6
Touch/Tilt Screen Adjustment 1-6
Setup Parameters 1-6
Cleaning 1-7
1-1

INTRODUCTION
The WY-30 is a low-cost, entry-level, ASCII display terminal. It
consists of a display console and a detachable keyboard. A user
enters information for display from the keyboard. The terminal
contains all of the electronics that support the display and
keyboard.
In addition to the cathode ray tube (CRT) and keyboard, the WY-30
contains two independent communications interfaces. Peripherals,
including a hard-copy printer or plotter, can be attached to the
terminal with interface connectors on the rear panel.
The component parts are organized around and controlled by the
microprocessor. The microprocessor controls all internal data
manipulation and processing functions.
HIGH LEVEL FUNCTIONAL DESCRIPTION
The terminal consists of a microprocessor and related logic, a
CRT controller and associated control logic, input/output (I/O)
devices, monitor and power supply circuitry, and a CRT. All
circuitry is mounted on a single printed circuit board (PCB), the
terminal PCB. The microprocessor controls all basic functions.
MICROCOMPUTER
The microcomputer comprises a clock and synchronization circuit,
program memory, 4K of RAM, a reset circuit, and the heart of the
terminal--a 2-megahertz, 6800-family microprocessor--the 68BOO.
MEMORY
Terminal memory consists of RAM and ROM. The microprocessor uses
4K of RAM for buffers, variable storage and system stack. The
video interface shares this RAM for screen refresh. Program
memory, 8K of ROM, holds all the terminal control firmware.
TERMINAL CONTROL
Functions of the terminal control firmware include keyboard
scanning, video control, data transfer to and from the
communication ports, and on-screen data manipulation.
INPUT/OUTPUT DEVICES
I/O devices consist of a CRT display, two communications
interfaces, and a keyboard.
1-2

CRT Display
The terminal has a 14-inch, flat-screen CRT. It displays 24 rows
of characters, 80 columns, and two control rows (one for terminal
status and the other for label, message, and setup). The CRT -
controller reads displayed characters from RAM on a direct memory
access (DMA) basis.
Communications Interfaces
The terminal has two asynchronous serial interfaces that conform
with the EIA standard RS-232C. Data rates are set for both
interfaces together. These parameters are operator controlled
and are defined in "Setup Parameters" in this chapter. Both
interfaces can communicate at data rates up to 38.4K bits per
second (bps).
Keyboard
The keyboard consists of 83 keys mounted on a single-sided PCB.
All keys are momentary action key switches. The microprocessor
periodically scans the keys checking for key closures.
Figure 1-1 shows the keyboard. You can find a detailed
description in Chapter 6, "Theory of Operations."
Figure 1-1 Keyboard
F5 ! 1=6 F7 F8
Ins Char Del Char Clr Line Replae'
ins Line Del. l,ne (II Page Insert
Send Copy PM A Page 'NYSE
Print P3ge 't' Page ",
[][][][][][][][][][][]O[] BackSpace LJ [][]CJt
LJ~~D~~D~~~~D~D~ ~~~[
DEJ[][J[]EJrJtJ~D[]DI Return 1[:] [][]~[
EJLJDDD[][][]E][][][[]LJLJEJ D[][][n,.
IcapsLock II l[JuDD DO
1-3

ENVIRONMENT
The terminal can be placed on a table, desktop, or any other
vibration-free horizontal surface that is free from lint and
dust. Abnormally bright room light or direct sunlight can
interfere with the display."
Figure 1-2 shows the WY-30 dimensions. The user should allow
three inches of clearance on all sides when installing the
terminal.
Users can install the terminal near most other types of electrical
or electronic equipment without serious interference. They should
avoid locations near strong magnetic fields that can distort and
interfere with the operating or servicing of the video display.
Figure 1-2 Terminal Dimensions
2'14" Extended
1 '12" Flat
Ambient room temperature should never exceed 45 degrees Celsius
(113 degrees Fahrenheit) when the terminal is on; however, the
terminal needs no special cooling. Users should make sure the
rear of the terminal has a free flow of air. They shouldn't set
the terminal on sound-deadening devices that block the flow of
air beneath it.
1-4