LA120 Technical Manual

Company:Digital Equipment Corporation
Part:EK-LA120-TM-001
Date:1980-01
Keywords:DECwriter III

Table of Contents

  • Chapter 1 Operator's Information
    • 1.1 Introduction
    • 1.2 Operator's Console
      • 1.2.1 Lights
      • 1.2.2 Local Control Keys
      • 1.2.3 SET-UP Keys
      • 1.2.4 Control Character Keys
      • 1.2.5 Other Keys
      • 1.2.6 Optional Numeric Keypad
      • 1.2.7 Power ON/OFF Switch and Voltage Selector Switch
      • 1.2.8 Cover Interlock Switch
      • 1.2.9 Paper Adjust Knob
      • 1.2.10 Tractor Adjust Knobs
      • 1.2.11 Carriage Adjustment Lever
    • 1.3 Alarm Indicators
    • 1.4 Operator Testing and Troubleshooting
  • Chapter 2 Installation, Interface, and Specifications
    • 2.1 Installation and Configuration
      • 2.1.1 Unpacking and Inspection
      • 2.1.2 Packing Procedures
      • 2.1.3 Checkout Procedure
      • 2.1.4 Answerback Jumper
    • 2.2 Interface Information
      • 2.2.1 Interface Signals
        • 2.2.1.1 Protective Ground
        • 2.2.1.2 Transmitted Data (TDX)
        • 2.2.1.3 Received Data (RDX)
        • 2.2.1.4 Request to Send (RTS)
        • 2.2.1.5 Clear to Send (CTS)
        • 2.2.1.6 Data Set Ready
        • 2.2.1.7 Signal Ground
        • 2.2.1.8 Carrier Detect (RLSD)
        • 2.2.1.9 Secondary Request to Send (SRTS)
        • 2.2.1.10 Speed Indicator (SPDI)
        • 2.2.1.11 Secondary Carrier Detect (SRLSD)
        • 2.2.1.12 Data Terminal Ready (DTR)
        • 2.2.1.13 Ring Indicator (RI)
        • 2.2.1.14 Speed Select (SPDS)
      • 2.2.2 EIA Interface Cables
        • 2.2.2.1 BC22A-10, -25
        • 2.2.2.2 BC22B-10, -25
      • 2.2.3 Impedance of Terminator
      • 2.2.4 Rise and Fall Times
      • 2.2.5 Open Circuit Voltage
    • 2.3 LA120 Specifications
  • Chapter 3 Programmer's Information
    • 3.1 General
    • 3.2 Escape Sequences
      • 3.2.1 Parser Program
      • 3.2.2 Sequence Descriptions
        • 3.2.2.1 Printer Character Sets
        • 3.2.2.2 Active Position
        • 3.2.2.3 Linefeed-Newline Mode
        • 3.2.2.4 Horizontal Pitch
        • 3.2.2.5 Horizontal Margins
        • 3.2.2.6 Horizontal Tabs
        • 3.2.2.7 Vertical Pitch
        • 3.2.2.8 Form Length
        • 3.2.2.9 Vertical Margins
        • 3.2.2.10 Vertical Tabs
        • 3.2.2.11 Product Identification
        • 3.2.2.12 Alternate Keypad Mode
    • 3.3 Control Characters
      • 3.3.1 Null or Delete (NULL or DEL)
      • 3.3.2 End of Text (ETX)
      • 3.3.3 End of Transmission (EOT)
      • 3.3.4 Enquiry (ENQ)
      • 3.3.5 Bell (BEL)
      • 3.3.6 Backspace (BS)
      • 3.3.7 Horizontal Tab (HT)
      • 3.3.8 Line Feed (LF)
      • 3.3.9 Vertical Tab (VT)
      • 3.3.10 Form Feed (FF)
      • 3.3.11 Carriage Return (CR)
      • 3.3.12 Shift In (SI)
      • 3.3.13 Shift Out (SO)
      • 3.3.14 Data Link Escape (DLE)
      • 3.3.15 Cancel (CAN)
      • 3.3.16 Substitute (SUB)
      • 3.3.17 Escape (ESC)
    • 3.4 APL Character Set
    • 3.5 Sample Form Setup Using Escape Sequences
    • 3.6 Synchronization
      • 3.6.1 Synchronization Limits
      • 3.6.2 Fill Time Formulas
        • 3.6.2.1 Horizontal Movement
        • 3.6.2.2 Vertical Movement
    • 3.7 Keyboard Operation
      • 3.7.1 Auto Repeat
      • 3.7.2 Printable Character Keys
      • 3.7.3 Control Character Keys
      • 3.7.4 CTRL (Control) Key
      • 3.7.5 Optional Auxiliary Keypad
      • 3.7.6 BREAK Key
      • 3.7.7 VIEW Key
  • Chapter 4 LA120 Theory of Operation
    • 4.1 Basic System Configuration
      • 4.1.1 Microprocessor
      • 4.1.2 Device Addressing
        • 4.1.2.1 Memory Space
        • 4.1.2.2 I/O Space
      • 4.1.3 Interrupts
      • 4.1.4 ROM
      • 4.1.5 RAM
      • 4.1.6 Keyboard
        • 4.1.6.1 Keyboard Addressing
        • 4.1.6.2 Switch Matrix
        • 4.1.6.3 Separately Decoded Keys
      • 4.1.7 Display
        • 4.1.7.1 LEDs
        • 4.1.7.2 Seven Segment Display
      • 4.1.8 Non-Volatile Memory
      • 4.1.9 DC305 Printer Controller
      • 4.1.10 8251A USART
      • 4.1.11 Utility I/O Ports
    • 4.2 DC305 Printer Controller
      • 4.2.1 Dot Print Control
      • 4.2.2 Carriage Position Count
      • 4.2.3 Carriage Speed Control
      • 4.2.4 Line Feed Control
      • 4.2.5 Bell Control
      • 4.2.6 Frequency Generation
      • 4.2.7 Tick Alarm
      • 4.2.8 Interrupt Vectors
    • 4.3 LA120 Firmware Overview
      • 4.3.1 Scheduling
      • 4.3.2 ROM Layout
      • 4.3.3 RAM Layout
    • 4.4 Print Control Firmware
      • 4.4.1 Starting the Print Operation
      • 4.4.2 Flight Time Compensation
      • 4.4.3 Dot Rate Limiting
    • 4.5 Carriage Servo Firmware
      • 4.5.1 Transitions
      • 4.5.2 Reading the Position Counter
      • 4.5.3 Carriage Speed Command
      • 4.5.4 Error Conditions
    • 4.6 Communication Firmware
      • 4.6.1 Communication Modes
      • 4.6.2 Local Mode
      • 4.6.3 Disconnects
      • 4.6.4 Full Duplex Without EIA Controls
      • 4.6.5 Full Duplex with EIA Controls
        • 4.6.5.1 Full-Duplex Break
        • 4.6.5.2 Full-Duplex Disconnect
        • 4.6.5.3 Restraint Mode
        • 4.6.5.4 Speed Control Mode
      • 4.6.6 Half Duplex
        • 4.6.6.1 Initial Direction Determination
        • 4.6.6.2 Reverse Channel
        • 4.6.6.3 Request to Send Delay
        • 4.6.6.4 Turnaround Characters
        • 4.6.6.5 Half-Duplex Break
        • 4.6.6.6 Half-Duplex Disconnect
      • 4.6.7 Communication State Control
        • 4.6.7.1 Communication State Table
        • 4.6.7.2 Communication Handler
      • 4.6.8 Control Code Generation and Detection
        • 4.6.8.1 Input Scanning
        • 4.6.8.2 Transmit Scanning
        • 4.6.8.3 Control Code Generation
      • 4.6.9 Functional State Diagrams
    • 4.7 Escape Sequence Processing
      • 4.7.1 Escape Sequence State Transition Table
        • 4.7.1.1 Element No. 1
        • 4.7.1.2 Element No. 2
        • 4.7.1.3 Element No. 3
        • 4.7.1.4 Element No. 4
        • 4.7.1.5 Element No. 5
        • 4.7.1.6 Element No. 6
        • 4.7.1.7 Element No. 7
      • 4.7.2 Escape Sequence Jump Table
      • 4.7.3 Escape Sequence Parser
        • 4.7.3.1 Begin Parsing
        • 4.7.3.2 Initialize Parser
        • 4.7.3.3 Flow Controller
      • 4.7.4 CSI Parameters
      • 4.7.5 Control Strings
      • 4.7.6 Final Character Perform-Function Routines
    • 4.8 SET-UP Command Processing
      • 4.8.1 SET-UP Command Implementation
        • 4.8.1.1 Multiple Choice SET-UP Commands
        • 4.8.1.2 Immediate Action SET-UP Commands
      • 4.8.2 SET-UP Handler
      • 4.8.3 SET-UP/Keyboard Handler Relationship
    • 4.9 Character Processing
      • 4.9.1 Character Reception
      • 4.9.2 Background Executive
      • 4.9.3 Print Line Builder
      • 4.9.4 Answerback Entry Handler
  • Chapter 5 Troubleshooting the LA120
    • 5.1 General
    • 5.2 DC Servo Test
    • 5.3 Encoder Duty Cycle Check/Adjustment
    • 5.4 Clock Test
    • 5.5 Wake Up Test
    • 5.6 Print Character Test
    • 5.7 USART Test
    • 5.8 Keyboard Test
    • 5.9 Line Feed Test
    • 5.10 Bell Test
  • Chapter 6 LA120 Subassembly Removal and Installation
    • 6.1 General
    • 6.2 Printer Housing
      • 6.2.1 Printer Housing Removal
      • 6.2.2 Printer Housing Installation
    • 6.3 Print Head Assembly
      • 6.3.1 Print Head Assembly Removal
      • 6.3.2 Print Head Assembly Installation
    • 6.4 Print Head Cable
      • 6.4.1 Print Head Cable Removal
      • 6.4.2 Print Head Cable Installation
    • 6.5 Timing Belt
      • 6.5.1 Timing Belt Removal
      • 6.5.2 Timing Belt Installation
    • 6.6 Print Bar
      • 6.6.1 Print Bar Removal
      • 6.6.2 Print Bar Installation
    • 6.7 Carriage Assembly and Front Carriage Shaft
      • 6.7.1 Carriage Assembly and Front Carriage Shaft Removal
      • 6.7.2 Carriage Assembly and Front Carriage Shaft Installation
    • 6.8 Carriage Eccentric Bearing and Lever
      • 6.8.1 Carriage Eccentric Bearing and Lever Removal
      • 6.8.2 Carriage Eccentric Bearing and Lever Installation
    • 6.9 Rear Carriage Shaft and Plain Bushing
      • 6.9.1 Rear Carriage Shaft and Plain Bushing Removal
      • 6.9.2 Rear Carriage Shaft and Plain Bushing Installation
    • 6.10 Ribbon Drive Pulley
      • 6.10.1 Ribbon Drive Pulley Removal
      • 6.10.2 Ribbon Drive Pulley Installation
    • 6.11 Ribbon Drive Assembly
      • 6.11.1 Ribbon Drive Assembly Removal
      • 6.11.2 Ribbon Drive Assembly Installation
    • 6.12 Ribbon Drive Fafnir Bearing
      • 6.12.1 Ribbon Drive Fafnir Bearing Removal
      • 6.12.2 Ribbon Drive Fafnir Bearing Installation
    • 6.13 Ribbon Eccentric and Backstop Spring
      • 6.13.1 Ribbon Eccentric and Backstop Spring Removal
      • 6.13.2 Ribbon Eccentric and Backstop Spring Installation
    • 6.14 DC Motor and Encoder Assembly
      • 6.14.1 DC Motor and Encoder Assembly Removal
      • 6.14.2 DC Motor and Encoder Assembly Installation
    • 6.15 Tractor Drive Shafts and Tractor Assemblies
      • 6.15.1 Tractor Drive Shafts and Tractor Assembly Removal
      • 6.15.2 Tractor Drive Shafts and Tractor Assembly Installation
    • 6.16 Idler Gear Assembly
      • 6.16.1 Idler Gear Assembly Removal
      • 6.16.2 Idler Gear Assembly Installation
    • 6.17 Stepping Motor Assembly
      • 6.17.1 Stepping Motor Assembly Removal
      • 6.17.2 Stepping Motor Assembly Installation
    • 6.18 Ribbon Chassis Assembly
      • 6.18.1 Ribbon Chassis Assembly Removal
      • 6.18.2 Ribbon Chassis Assembly Installation
    • 6.19 Ribbon Spool Ratchet Wheels and Friction Disks
      • 6.19.1 Ribbon Spool Ratchet Wheel(s) and Friction Disk Removal
      • 6.19.2 Ribbon Spool Ratchet Wheel(s) and Friction Disk Installation
    • 6.20 Keyboard/Numeric Pad Assembly
      • 6.20.1 Keyboard/Numeric Pad Assembly Removal
      • 6.20.2 Keyboard/Numeric Pad Assembly Installation
    • 6.21 Power Supply Assembly
      • 6.21.1 Power Supply Assembly Removal
      • 6.21.2 Power Supply Assembly Installation
    • 6.22 Printer Mechanism Assembly
      • 6.22.1 Printer Mechanism Assembly Removal
      • 6.22.2 Printer Mechanism Assembly Installation
    • 6.23 CVT Power Supply Module
      • 6.23.1 CVT Power Supply Module Removal
      • 6.23.2 CVT Power Supply Module Installation
    • 6.24 Power Entry Bracket Assembly
      • 6.24.1 Power Entry Bracket Assembly Removal
      • 6.24.2 Power Entry Bracket Assembly Installation
    • 6.25 Fan
      • 6.25.1 Fan Removal
      • 6.25.2 Fan Installation
    • 6.26 Logic/Power Board
      • 6.26.1 Logic/Power Board Removal
      • 6.26.2 Logic/Power Board Installation
  • Chapter 7 Adjustment Procedures and Lubrication
    • 7.1 Print Head Adjustment
    • 7.2 Printer Mechanism Adjustment
    • 7.3 Paper Guide Adjustment
    • 7.4 Paper Out Switch Adjustment
    • 7.5 Ribbon Tension Adjustment
    • 7.6 Ribbon Drive Assembly Adjustment
    • 7.7 Idler Gear Assembly Adjustment
    • 7.8 Bumper Assembly Adjustment
    • 7.9 Print Bar Adjustment
    • 7.10 Lubrication
  • Chapter 8 20 mA LA12X-AL Option
    • 8.1 General
    • 8.2 Installation
    • 8.3 Test After Installation
    • 8.4 Electrical Characteristics
      • 8.4.1 Transmitter
      • 8.4.2 Receiver
      • 8.4.3 Pin Assignments
  • Chapter 9 Expanded Buffer Option LA12X-DL
  • Chapter 10 LA120-RE
    • 10.1 Introduction
    • 10.2 Installation
  • Chapter 11 LA12X-HL Keyboard Option
    • 11.1 Introduction
    • 11.2 Installation
    • 11.3 Operator's Information
  • Chapter 12 LA12X-YL Option
    • 12.1 Introduction
    • 12.2 Installation
    • 12.3 Operator's Information
      • 12.3.1 Indicator Lights
      • 12.3.2 Control Keys
      • 12.3.3 SET-UP Mode
      • 12.3.4 Baud Rate (Speed)
      • 12.3.5 Parity and Data Bits
      • 12.3.6 Setting Form Length
      • 12.3.7 Printer New Line Character
      • 12.3.8 Modem
      • 12.3.9 Secondary Channel
      • 12.3.10 Status
      • 12.3.11 Store/Recall
  • Appendix A LA120 Operator Reference Card
  • Appendix B Factory Parameter Settings

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