Lear Siegler ADM-3 User manual

ADM-3
DUMB TERMINAL
MAINTENANCE MANUAL

Section
TABLE OF CONTENTS
Page
1
2
3
GENERAL DESCRIPTION. . . . .
1.1 INTRODUCTION
...
1.2 ADM-3 CAPABILITIES . . . . ..
1.3 PHYSICAL DESCRIPTION. .
1.4 SPECIFICATIONS . . . . . .
INSTALLATION. .......
2.1 GENERAL
...
2.2 VISUAL INSPECTION
2.3 INSTALLATION. . .
2.4 SETTING INTERNAL SWITCHES. .
2.5 SETTING FRONT PANEL SWITCHES .......
2.6 SETTING DISPLAY CONTROLS . .
2.7 CONNECTING CABLES &TURNING
ON POWER
OPERATION .
3.1 GENERAL . . . . . . . . . . . . . . . . . . .
3.2 DISPLAYABLE CHARACTERS. .....
3.3 SPECIAL FUNCTION KEYS .
3.4 PROGRAMMING AND WORD STRUCTURE
3.4.1 Remote Control
Functions. .....
3.4.2 Data Character
Format . .
3.4.3 Data Transmission
Format . . . . . .
1-1
1-1
1-1
1-1
1-2
2-1
2-1
· 2-1
· . . . . . 2-1
. 2-1
· 2-3
· 2-4
2-4
· . . . . . 3-1
....... 3-1
3-1
3-1
·3-2
3-2
3-4
3-5
GENERAL .
GENERAL FUNCTIONAL DESCRIPTION
Display Generation ......
Display Refresh Operation ...
Monitor Video and Drive Circuits
Receiving and Storing
Data. .
Cursor Generation . . .
Keyboard Logic . . . .
Data Transmitter Logic
Interface Control Logic
CRT Display Monitor
LOGIC DESCRIPTION .
General Clear Circuit
Display
Counters. .
Offset Counter Logic
4THEORY OF OPERATION. ......
4.1
4.2
4.2.1
4.2.2
4.2.3
4.2.4
4.2.5
4.2.6
4.2.7
4.2.8
4.2.9
4.3
4.3.1
4.3.2
4.3.3
· . 4-1
· . 4-1
· . 4-1
· . 4-1
·4-1
·4-1
· . 4-1
· . 4-3
.4-3
.......... 4-3
· . 4-4
.4-4
4-4
......... 4-4
4-4
4-6

TABLE OF CONTENTS (cont'd)
Section
Page
4THEORY OF OPERATION (cont'd)
4.3.4 Cursor Control Logic .........
4.3.5 Memory Address Logic .........
4.3.6 Refresh Memory and Character
ROM Logic.
4.3.7 Erase
Logic. . .
4.3.8 Write Pulse Logic. .
4.3.9 Keyboard Logic .
4.3.10 Beeper Logic . . . . . .
4.3.11 Data Receiver and Command Decoder Logic
4.3.12 Data Transmitter Logic .....
4.3.13 Video Blanking and Serializer Logic. .
4.3.14 Monitor Drive Logic.
.. ....
4.3.15 Baud Rate Select Logic. . . . . . . .
4.3.16 Interface Control Logic . . . .
4.3.16.1 Code Turnaround Control
4.3.16.2 Reverse-Channel
Control. . .
4.3.17 Power Supplies. .
.. .
4.3.18 CRT Display Monitor .
4.3.19 Answerback O.ption. ...
4.3.20 Extension Current Loop .
4.3.21 Extended Numeric Keypad . . . . . .
4-7
4-7
·
.. 4-11
· .
.. 4-13
·
..... 4-13
. . . .. .. 4-13
4-15
4-16
.
.... 4-16
4-18
·4-19
·
..... 4-19
· . 4-20
·
.. 4-20
· . 4-20
·
.. 4-21
. . . . . . 4-21
· . .. 4-25
.
... 4-25
·4-25
5-1
· . 5-1
....... 5-1
· 5-1
· . 5-1
· . . 5-1
· 5-1
· . 5-1
· 5-1
· 5-3
5-3
5-3
5-3
· . 5-3
... 5-3
.... 5-4
5-4
· . 5-8
· . 5-8
· . 5-8
MAINTENANCE. . . . . . .
5.1 GENERAL ........
5.2 INSTALLATION. .
5.3 ROUTINE MAINTENANCE
5.4 OPENING
ADM-3 COVER. .
5.5 ADJUSTMENTS. '
.....
5.5.1 Contrast Adjustment . .
5.5.2 Brightness Adjustment. .
5.5.3 Low Voltage Supply. .
5.5.4 Vertical Adjustments .
5.5.5 Horizontal Adjustments .....
5.5.6 Focus Adjustment . . .
5.5.7 Centering. . . . . . . . . . . .
5.6 CORRECTIVE MAINTENANCE. .
5.6.1 Failure Analysis ..........
5.6.2 Troubleshooting the Monitor . . . .
5.6.3 Removing and Replacing Monitor CRT and Subassemblies. .
5.6.4 Troubleshooting the Main Circuit
Board. . . . .
5.6.5 Removing and Replacing the Main Circuit Board. .
5.6.6 Removing and Replacing Key Switch Contacts
5
ii

TABLE OF CONTENTS (cont'd)
Section Page
6-1
·6-1
6-1
6-7
6-7
6-7
... 6-8
·6-8
· . 6-11
· . 6-16
6-16
.
.... 6-16
· . 6-16
6-16
· . 6-19
....... 6-19
......
.. 6-19
.... 6-19
·6-19
·6-21
.
..... 6-25
·6-25
...... 6-25
·6-26
·6-28
. . . .. 6-31
··.··6-34
· · 6-35
· · · 6-36
· · 6-37
DRAWINGS, ,......................
6.1 SCHEMATIC SHEET
#2 -System Counters . .
6.2 SCHEMATIC SHEET #11 -Interface
Control. .
6.3 SCHEMATIC SHEET
#3.. . .
6.3.1 Offset Counter.
6.3.2 Cursor Registor . . .
6.3.3 Beeper
Circuit. .............
6.4 SCHEMATIC SHEET #4 -Memory Address Generation. .
6.5 SCHEMATIC SHEET #5 -Data Receiver/Decoder.. .....
6.6 SCHEMATIC SHEET #6. . . . . " . . . . .
6.6.1 Clear Circuit. . . . .
6.6.2 Read Back . . . . . . . . .
6.6.3 Monitor Drive Signals .
6.6.4 Cursor Generation . .
6.7 SCHEMATIC SHEET
#7 ...
6.7.1 Refresh Memory. .
6.7.2 Character Generators
6.7.3 Video Serializer . . .
6.7.4 Transmit Data Multiplexers.
6.8 SCHEMATIC
#8 -Keyboard Circuit
6.9 SCHEMATIC SHEET
#9 . . .
6.9.1 Data
Transmitter. .....
6.9.2 Control Section of UART. .
6.9.3 Current Loop SMTR/RCVR ......
'. .
6.10 SCHEMATIC SHEET
#10 -Baud Rate Generation. .
6.11 CRT DISPLAY MONITOR .
6.12 P.C. BOARD ASSEMBLY .
6.13 CIRCUIT BOARD
FRONT. . .
6.14 CIRCUIT BOARD BACK
....
6.15 POWER SUPPLY SCHEMATIC
6
7PARTS LIST .
7-1
8RETURNING EQUIPMENT
FOR REPAIR. · ·
8-1
9PAINT
.....
9-1
APPENDIXA ..
·A-I
APPENDIXB .· ·
B-1
iii

LIST OF ILLUSTRATIONS
Figure Page
2-1
2-3
2-4
..... 4-2
4-3
4-4
..... 4-5
..... 4-6
·4-8
... 4-9
·4-9
·4-10
4-11
4-12
4-14
4-16
·4-17
4-18
4-19
·4-21
.. 4-22
ADM-3 Internal Switches and Controls
ADM-3
Front Panel Switches .....
Background Intensity ·Control. . . . . . . .
ADM-3 Interactive Display Terminal, Functional Block Diagram. . .
CRT Display Matrix. . . . . . . . . . .
Display Counters, Block Diagram. . .
Display Counter Timing . . . . . .
Offset Counter Logic, Block Diagram .
·Clear Screen Timing. . . . . . .
Cursor Control Logic, Block Diagram
Memory Address Logic, Block Diagram .
Manipulation
of Display Address. . . .
Organization
of Display Data in Refresh Memory. .
Refresh Memory and Character ROM Logic, Block Diagram
Keyboard Logic Timing ..............
Data Receiver and Command Decoder Logic, Block Diagram
Data Transmitter Logic, Block Diagram ......
Video Blanking and Serializer Logic, Block Diagram
Baud Rate Select Logic, Block Diagram . . . . .
Interface Timing for Code Turnaround . . . . .
Interface Timing for Reverse-Channel
Operation. .
2-1
2-2
2-3
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
5-1
5-2
5-3
5-4
5-5
5-6
5-7
5-8
5-9
5-10
Interface Connector Terminal Assignments. .
Inputs
to Monitor, Timing Diagram. . .
Monitor Voltage Waveforms. ........
Monitor Video Board,
Component Layout. .....
Removing and Replacing Key Switch Contacts, Step d
Removing and Replacing Key Switch Contacts, Step g
Removing and Replacing Key Switch Contacts,
Step h-1.
Removing and Replacing Key Switch Contacts, Step h-2. . .
Removing and Replacing Key Switch Contacts, Step i .
Removing and Replacing Key Switch Contacts, Step
I. .....
· 5-2
· 5-5
5-6
..... 5-7
·5-11
... 5-12
·5-13
· . 5-14
· . 5-15
....... 5-16
6-1
6-2
6-3
6-4
6-5
6-6
6-7
6-8
Display Counter Timing . . . . . .
Basic Counters. . . . . . . . . . .
Interface Timing for Code Turnaround
Interface Timing for Reverse-Channel
Operation.
Interface Control. .
Clear Screen Timing. . . . . . . . . . . . .
Offset Line Counter. . . . . . . . . . . . .
Manipulation
of Display Data in Refresh Memory' .
6-2
· 6-3
· . 6-4
6-5
· 6-6
· 6-9
·6-10
·6-13
iv

Figure
6-9
6-10
6-11
6-12
6-13
6-14
6-15
6-16'
6-17
6-18
6-19
6-20
6-21
6-22
6-23
6-24
6-25
LIST OF ILLUSTRATIONS (cont'd)
Organization of Display Data in Refresh Memory. .
MUX
.....
Operation Initiate.
Read Mode
....
Cursor Generation . . . .
Memory Refresh, Video
Keyboard Logic TIming .
Keyboard
..
Current Loop . . . . .
Baud Rate
.....
Monitor Interconnecting Cabling Diagram
Monitor Circuit Board Components Location .
Schematic, TV9 and
12 With Power Supply.
P.C. Board Assembly
Circuit Board
Front.
Circuit Board Back .
Power Supply . . . .
v
Page
6-13
· . 6-15
6-17
· . 6-18
. ... 6-20
. . .. 6-23
·6-24
6-27
·6-29
·6-30
6-31
...... 6-32
·6-33
6-34
6-35
· . 6-36
· . 6-37

Table
1-1
1-2
3-1
3-2
5-1
LIST OF TABLES
Monitor
Input Data Specifications .
CRT Display Specifications.
ADM-3 Control
Codes. .
ASCII Character Codes
Main Circuit Board Connector Terminals.
vi
Page
1-3
1-4
3-3
. 3-4
5-19

1.1 INTRODUCTION
SECTION 1
GENERAL DESCRIPTION
1.3 PHYSICAL DESCRIPTION
This manual contains a general description,
installation and operating instructions, theory
of operation, and maintenance information for
the Lear Siegler ADM-3 Interactive Display
Terminal.
Additional information is contained in the
ADM-3 Operator's Handbook. The mainte-
nance technician should be thoroughly famil-
iar with material in the Operator's Handbook
before
attempting to troubleshoot or repair the
ADM-3.
1.2 ADM-3 CAPABILITIES
The ADM-3 has the following general
capabilities:
a. Receives USASCII-coded
data from are-
mote
computer and displays it on aCRT
screen displaying up to 960 characters
(1920 characters, optional).
b.
Permits the operator, using a,keyboard,
to compose amessage, visible on
the screen
as it is transmitted to the remote computer
or other device.
c. Through an extension port, permits inter-
facing with ahard-copy printer, magnetic
tape recorder, or other terminals.
d. Provides for full-duplex or half-
duplex communications, through either
an RS -232C or current-loop interface.
e.
Permits 202 communications line
turnaround by means of either EOT or
ETX code-turnaround (in which the con-
trolling device transmits a turnaround
code to give control to the device at the
other end of the line), or secondary-
channel turnaround(in which asecondary
channel selection establishes control of a
device for
data transmission through the
primary channel).
1-1
Principal components of the ADM-3 are as fol-
lows:
a. Amolded case comprising a
base and a
cover. The base contains the power
switch, power transformer, beeper
speaker, and inter component cabling.
The main circuit board rests on supports
molded in the base and is held in place by
two guide pins.
The cover contains the monitor CRT and
other monitor subassemblies. It is hinged
at the rear so that all components of the
ADM-3 are accessible when it is opened.
The cover is easily removed by swinging
it back as far as it will go, and then' slid-
ing it to the left, off the hinge pins. (The
monitor-connecting cable
must be discon-
nected.)
b.
The main circuit board which contains all
elements of the ADM-3 except monitor,
power switch and transformer, and
beeper speaker. The keyboard consists of
integrated key rows and is built directly
on the main circuit board.
The main circuit board rests on supports
within the base and is held in place by
guide pins. Two connectors on the rear
edge of the board provide the RS-232C
and current loop (optional printer port)
interface at both the main. and extension
ports.
c. The CRT monitor which comprises three
subassemblies, as follows:
1.
The CRT itself. The CRT is mounted
in a metal frame with its face held
against the cover bezel by two brackets,
each retained by asingle screw.

KEYBOARD
59-key solid-state keyboard designed similar
to a teletypewriter layout and containing the
following keys:
2. A printed circuit board (video board)
containing most circuits of the
monitor. The video board is held in
place by the cover molding on one side,
and by pressure of the flyback assem-
bly on the other.
3. The flyback assembly, which is held in
place by asingle screw. Bosses in the
cover molding assembly surface retain
the edge of the video board.
1.4 SPECIFICATIONS
47 alphanumeric keys
RETURN
LINE FEED
RUB
HERE IS
SHIFT
COMMUNICATIONS
CTRL (Control)
BREAK
CLEAR
REPT (Repeat)
ESC (Escape)
Space
Bar
DISPLAY
Screen
12-inch (diagonally measured) rectangular
CRT with P4 white phosphor and etched non-
glare surface.
Display Format
Standard: 960 characters, 12 lines of 80
characters
Optional: 1920 characters, 24 lines of 80
characters
Character Set
Generated: 128 ASCII characters (upper and
lower case, numeric, punctuation
and control)
Displayed:
Standard -64 ASCII characters
(upper case, numeric,
punctuation)
Optional- 95 ASCII characters
(upper and lower
case, numeric, punc-
tuation)
Character Generation
5 x 7 dot matrix, 0.18 in. high x0.075 in. wide
Cursor
Underline, homes to lower left of screen
Data Entry
New data enters on bottom line of screen; line
feed causes upward scrolling of entire display
page
with top-of-page overflow.
Refresh Rate
.60Hz or 50Hz, dependent on an internal switch
set to match power line frequency.
1-2
Modem Interface
EIA standard RS-232C and 20mA current loop
(switch selectable)
Extension Interface
Extension RS-232C port for interfacing serial
asynchronous auxiliary device (e.g., hard copy
printer, magnetic tape recorder or additional
data terminals).
Optionally, the extension port is available
with both RS-232C and 20mA current loop in-
terfaces.
Communication Rates
75,110,150,300,600,1200,1800,2400,4800,
9600, 19200 baud (switch selectable)
Send/Receive Modes
Full duplex and half duplex (switch selectable)
Word Structure
Total word length is switch selectable to 9, 10
or 11 bits consisting of the following:
7-bit
data word 1 start bit \
8th bit - parity, odd or even 1 or 2stop bittj
OR
forced to 1
or 0
OR
8th bit suppressed
PHYSICAL AND ELECTRICAL
Dimensions
13.5 in. high x15.5 in. wide x19 in. deep