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

OPERATOR INTERFACES
Figure 1-3 shows all operator interfaces, including the keyboard,
power cord, and brightness slideswitch. It also points out the
MODEM and AUX ports.
Figure 1-3 Operator Interfaces
Power ON/OFF
Power Cord
--.-,;?
Keyboard
Plug the keyboard cable connector into the keyboard connector
jack on the left side of the terminal.
1-5

Power Cord
Insert the power cord into the connection on the rear panel, and
then plug the three-pronged connector into the AC power source.
Caution--Compare the voltage specified on the configuration label
(on the back of the CRT enclosure) with the AC power source to
avoid damaging the terminal.
Communications Cable
Connect the communications cable from the computer or modem to
the communications port labeled MODEM. This port defaults at
9600 baud, no parity, with one stop bit and eight data bits. The
operator can change these parameters in setup mode.
AC Power Switch
The power switch is on the right side of the terminal. Pressing
the back of the switch turns AC power on.
Brightness Slideswitch
The brightness slideswitch is located on the lower-right corner
of the front bezel. Sliding the switch to the right increases
the display brightness; sliding it to the left decreases the
brightness.
Touch/Tilt Screen Adjustment
The touch/tilt screen adjustment is a spring-controlled support
flap on the bottom of the terminal enclosure. A user can adjust
the angle at which he views the screen by pushing or pulling the
terminal bezel.
SETUP PARAMETERS
When a user turns the power on, the terminal executes an internal
self-test. When the self-test finishes and the CRT is warm
(approximately 30 seconds), the cursor appears in the upper
left-hand corner of the display. The unit is now ready for
operation based on the setup parameters.
To inspect the parameters, press both the SHIFT and SETUP keys.
The first level of parameters appears across the bottom of the
screen. To examine the other levels of parameters, press the
CURSOR DOWN key. Each time you press this key, you can see
another 1 ev e 1.
1-6

To change the parameters, follow these steps:
1. Enter setup mode by pressing the SHIFT and SETUP keys.
2. Press CURSOR DOWN until the parameter to be changed is
displayed in the setup line, the row of highlighted fields
at the bottom row of the screen.
3. Press CURSOR RIGHT or LEFT until the specific parameter to
be changed is highlighted.
4. Press the spacebar to advance the parameter to the specific
setting desired.
5. Press the cursor keys as required to advance to the next
parameter to be changed.
6. To leave setup mode, press the SHIFT and SETUP keys.
The status line flashes a message asking if the changed
parameters should be saved for power-on. Parameter changes
are implemented immediately.
Pressing the Y key saves the parameters that you keyed in.
Pressing the N key saves all changes temporarily. The new
parameters are effective only until you turn off the power.
Pressing the ESC key returns all parameters to their factory
default values.
Pressing the ENTER key restores all parameters from memory
before leaving setup mode.
7. To return to a normal operation mode, press any key.
The terminal is now operational using the parameters defined in
the setup mode.
See the WY-30 User's Guide for more comprehensive setup
instructions.
CLEANING
You may find that the terminal needs to be cleaned when you've
finish servicing it. The screen should be cleaned with a soft,
lint-free cloth. Apply a safe cleaner to the cloth, not directly
to the screen.
Caution--Don't ever clean the screen with chemical substances,
abrasives, or commercial glass cleaners that contain alcohol or
ammonia.
1-7

2 REMOVAL AND REPLACEMENT PROCEDURES
Overview
...................................................
2-2
Before You Start 2-2
Safety 2-2
Required Tools 2-3
Removing and Replacing Assemblies in the
Keyboard Module 2- 3
Keyboard ;:, 2-3
Keyboard Cable 2-4
Keyboard PCB 2-5
Removing and Replacing Assemblies in the
Terminal Module 2-5
Removing the Terminal Enclosure 2-6
Replacing the Fuse 2-7
Replacing the Terminal PCB 2-8
Replacing the CRT/Yoke Assembly 2-10
Replacing the yoke ·········· 2-12
Replacing the Terminal Enclosure 2-13
Discharging the Anode 2-13
2-1

OVERVIEW
This chapter explains how to remove and replace assemblies and
components in both terminal modules. For purposes of
orientation, "front" is the monitor face, and "back" is the rear
panel and power cord location.
The terminal consists of two major modules (see Figure 2-1):
o
o
Terminal
Keyboard
The terminal module includes the CRT/yoke
assembly and the terminal PCB. The terminal
PCB holds all control logic, power supply
circuitry, and the circuitry to amplify and
display horizontal, vertical, and video
signals on the CRT screen.
The keyboard module includes the keyboard PCB
and the keyboard cable.
Figure 2-1 Terminal Modules
Termlnal--'"
"h~- Keyboard
BEFORE YOU START
Safety
Warning--This terminal contains high voltage. Don't attempt to
service the terminal without taking all the precautions necessary
to work with high voltage, including the following:
o If you must open the terminal for any reason, turn off the
power, disconnect any communications cables, and unplug the
terminal.
2-2

oRemove any jewelry, especially on hands and wrists.
o Avoid wearing clothing that holds a static charge.
oUse only insulated or nonconductive tools.
o Whenever you disconnect the anode lead from the anode,
make sure to ground the anode as directed in "Discharging
the Anode."
o If you need to remove or replace the CRT/yoke assembly,
remember that it can implode if you drop it or break the
neck. The flying glass can injure anyone within a radius
six to ten feet.
Required Tools
Before you remove or replace any assemblies in the terminal, ma
sure you have the tools and materials listed below.
oNo. a Phillips screwdriver
oNo. 2 Phillips screwdriver
o Insulated flat-blade screwdriver
o Alligator clips
o Digital multimeter (or voltmeter)
o Nonscratch mat or surface
o Fuse puller or small flat-blade screwdriver
REMOVING AND REPLACING ASSEMBLIES IN THE KEYBOARD MODULE
This section describes procedures to remove and replace the
keyboard, keyboard cable, and keyboard PCB.
Keyboard
Tools required: None
To replace the keyboard (see Figure 2-2), follow these steps:
1. Turn off the terminal.
2. Press the keyboard cable connector tab and pull the keyboa
cable out of the keyboard.
3. Plug the keyboard cable into the new keyboard's connector.
2-3

Figure 2-2 Keyboard Assembly
Bottom Cover
Cable Connector r
Keyboard Cable
Cable
ESD Shield
..&"!iill~_--Prlnted Circuit Board
Top Cover
For Service Manuals
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8 Cherry Tree Road, Chlnnor
Oxford.hlre, OX9 4QY.
Tel [phone]
Fax [phone]
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Tools required: None
To replace the keyboard cable (see Figure 2-2), follow these
steps:
1. Turn the terminal off.
2. Press the keyboard cable connector tab and pull the keyboard
cable out of the keyboard.
3. Press the other keyboard cable connector tab and pull the
keyboard cable out of the left side of the terminal.
4. Insert one end of the new keyboard cable into the keyboard
connector. Insert the other end into the left side of the
terminal.
2-4

Keyboard PCB
Tools required: No. 0 Phillips screwdriver
No. 2 Phillips screwdriver
To replace the keyboard PCB (see Figure 2-2), follow these step
1. Turn off the terminal.
2. Unp 1ug the keyboard cab 1e from the keyboard.
3. Turn the keyboard over and remove the six No.2 Phillips
screws that attach the keyboard bottom cover to the
keyboard.
4. Lift off the keyboard bottom cover.
5. Remove the No. 0 Phillips screw beneath the spacebar
that holds the keyboard top cover to the PCB assembly.
6. Unscrew the three No. 0 Phillips screws and washers that
hold the keyboard ESD shield on the keyboard PCB.
7. Lift the PCB assembly out of the keyboard cover.
8. Cover the under side of the new keyboard PCB with the
keyboard ESD shield. Replace the screws and washers.
Tighten.
9. Fit the new keyboard PCB assembly back into the keyboard t
cover.
10. Replace the No. 0 Phillips screw that holds the PCB assemb
in place.
11. Reattach the bottom cover of the keyboard assembly.
12. Plug the keyboard cable back into the terminal.
REMOVING AND REPLACING ASSEMBLIES IN THE TERMINAL MODULE
This section describes removing and replacing the terminal
enclosure, the fuse, the terminal PCB, and the CRT/yoke assembl
It also describes how to discharge the CRT anode.
2-5

Removing the Terminal Enclosure
Tool required: No.2 Phillips screwdriver
To remove the terminal enclosure (see Figure 2-3), follow these -
steps:
1. Remove all cables and power cords from the rear of the
terminal.
2. Rest the display face of the terminal on a nonscratch
surface.
3. Disconnect the keyboard cable on the left side of the
terminal enclosure.
4. Remove two No.2 Phillips screws from the rear panel of
the terminal enclosure.
5. Remove two No.2 Phillips screws from the bottom of the
terminal enclosure, next to the back bezel.
6. Lift off the terminal enclosure.
Figure 2-3 Removing the Terminal Enclosure
2-6

Replacing the Fuse
Tool required: Fuse puller or screwdriver
The terminal has one fuse, rated 2 amps, 125 volts. See Figure
2-4 for the fuse location on the terminal PCB.
To
check or replace the fuse, follow these steps:
1. Remove the terminal enclosure.
2. Use a fuse puller to remove the suspected fuse.
3. Check the fuse. If the fuse is broken or blackened, push a
new fuse into the fuse socket.
If the fuse is good, push it back into the fuse socket.
4. Replace the terminal enclosure (see "Replacing the Termina
EnClosure" for instructions).
Figure 2-4 Replacing the Fuse
2-7