Mitsubishi Electric LS Pro, Apricot LS Pro Hardware Technical Reference
HARDWARE TECHNICAL REFERENCE
LS Pro
apricot
MITSUBISHI ELECTRIC
HARDWARE TECHNICAL REFERENCE
386 and 387 are trademarks of Intel Corporation.
SCAMP is a trademark of VLSI Technology Inc.
Cyrix is a trademark of Cyrix Corporation.
National Semiconductor is a registered trademark of National Semiconductor Corporation.
Cirrus Logic is a registered trademark of Cirrus Logic Inc.
Information contained in this document is subject to change without notice and does not represent a commitment on the part of
Apricot Computers Limited. The software described in this manual is furnished under a license agreement. The software may be used
or copied only in accordance with the terms of this agreement.
It is against the law to copy any disk supplied for any purpose other than the
purchaser’s personal use.
All rights reserved; no use or disclosure without written consent.
Copyright © Apricot Computers Limited 1993
Published by
Apricot Computers Limited
3500 Parkside
Birmingham Business Park
Birmingham B37 7YS
MITSUBISHI ELECTRIC
Printed in the United Kingdom
Part no. 15050131
Preface
The Apricot LS Pro Technical Reference Manual is intended for:
Programmers and engineers involved in hardware and software design for LS Pro
computers.
Contents
Preface
Service personnel involved in fault diagnosis and repair.
All computers in the Apricot LS Pro range are covered.
The manual is divided into a number of sections and appendices as described below:
1. Introduction This is a brief overview of the Apricot LS Pro which describes the options and major
components of the system.
2. System Unit This section describes the system unit: it also includes disassembly instructions for
servicing and replacing major components of the system. It includes pinouts of the
connectors which appear on the rear of the system unit.
3. System Board This section provides an overview of the function of the system board and more
detailed descriptions of the processor and interface circuitry. Sub-sections provide a
description of each area of the board.
4. Peripheral This section describes each of the system components which attach to either the
Items system board e.g. floppy disk drive, or system unit e.g. keyboard. Also included is brief
information on the KeyLOC card. Sub-sections describe each component.
5. Memory and This section provides information on the usage of Memory and I/O space by
I/O space the LS Pro system board, and programming information for each part of the system.
Chapter 1
Chapter 2
Chapter 3
Appendices Three appendices are included:
Appendix A
This contains specifications for each component of Apricot LS Pro computers.
Appendix B
This appendix describes the differences between the revision C system board and the
revision D system board described in section 3.
Appendix C
A list of error beep codes.
Chapter 5
Chapter 6
LS PRO HARDWARE TECHNICAL REFERENCE 1
Preface
Associated Publications
Preface
ContentsChapter 1
Chapter 2
The following publication may be of general use to engineers and programmers.
IBM Personal Computer AT Technical Reference Manual.
The following manufacturers data sheets give information on specific devices:
Intel 80386SX
80387SX
8042 Keyboard controller
82077 Floppy disk controller
8237 DMA controller
8254 System timers
8259 Interrupt controllers
82596 Ethernet coprocessor
VLSI VL82C311 (SCAMP) AT chipset
Cyrix 486SLC
Cirrus CL-GD542X video controller
National Semiconductor NS16450 Serial communications controller
Chapter 3
Chapter 5Chapter 6
Hitachi MC146818 Real time clock
2 LS PRO HARDWARE TECHNICAL REFERENCE
CONTENTS
Contents
Contents
1 INTRODUCTION
General....................................... 1/2
Variants....................................... 1/2
System unit ................................ 1/3
Keyboard.................................... 1/3
Monitors..................................... 1/4
Expansion ................................... 1/4
2 SYSTEM UNIT
Introduction............................... 2/2
External layout.......................... 2/2
Internal layout ........................... 2/3
Servicing level............................ 2/3
Dismantling and re-assembly . 2/3
Installing add-ons ....................2/16
System unit connectors ........2/20
3 SYSTEM BOARD
3.1 Introduction ........................... 3/2
General....................................... 3/2
Description ................................ 3/4
3.2 Processor system ................ 3/5
Address and data bus
structure..................................... 3/5
Software compatibility.............3/5
Modes of operation ................. 3/5
3.3 SCAMP ..................................... 3/6
Interrupt structure................... 3/6
Direct Memory Access ........... 3/8
System timers............................ 3/9
3.4 System memory.................3/10
General.....................................3/10
Read only memory (ROM)...3/10
Random access memory
(RAM) ....................................... 3/10
Real time clock (RTC) RAM 3/11
3.5 Video adapter......................3/14
General.....................................3/14
3.6 Floppy disk controller .....3/15
General.....................................3/15
Drive formats..........................3/15
3.7 Hard disk interface ...........3/16
General.....................................3/16
Interface signal descriptions.3/16
3.8 Peripherals controller .....3/17
Serial ports...............................3/17
Parallel port ............................. 3/18
3.9 Keyboard/mouse
controller...............................3/18
General.....................................3/18
Keyboard password security3/18
3.10 LOC Technology ...............3/19
3.11 Ethernet port ...................... 3/19
General.....................................3/19
3.12 Apricot Business Audio ..3/21
3.13 System board
connectors ............................3/21
Hard disk drive connectors .3/21
Floppy drive connector.........3/22
System board power
connector.................................3/22
Battery jumper........................3/22
4 PERIPHERAL ITEMS
4.1 Power supply ......................... 4/2
Description ................................ 4/2
Connector ................................. 4/3
4.2 Monitors ................................... 4/3
Introduction............................... 4/3
Maintenance............................... 4/4
Video signal................................ 4/4
Apricot SVGA colour
monitor....................................... 4/4
External controls...................... 4/4
HiVision Low Emission 14"
colour.......................................... 4/6
HiVision Low Emission 17"
colour.......................................... 4/7
VGA connector ........................ 4/9
4.3 Hard disk drives ................... 4/9
Introduction............................... 4/9
Quantum ProDrive ELS .......... 4/9
Maxtor 7213A.........................4/11
Quantum ProDrive
LPS240AT.................................4/12
Quantum ProDrive
LPS525AT.................................4/13
IDE interface............................4/14
Chapter 1
Contents
Contents
Chapter 2
Chapter 3
Chapter 3
Chapter 5
LS PRO HARDWARE TECHNICAL REFERENCE 1
Contents
Contents
Contents
Chapter 1
Chapter 2
Chapter 3
4.4 Floppy drive .........................4/16
Description ..............................4/16
Interface....................................4/17
4.5 Keyboard ...............................4/18
Introduction.............................4/18
Operation.................................4/19
Scan codes ...............................4/22
4.6 KeyLOC card .......................4/29
5 MEMORY AND I/O USAGE
5.1 Introduction ........................... 5/2
5.2 Memory usage.......................5/2
5.3 I/O space .................................. 5/4
DMA I/O address map............ 5/5
Interrupt controllers ............... 5/6
System timers............................ 5/6
Keyboard controller................ 5/6
Port B.......................................... 5/8
RTC RAM/NMI mask .............. 5/9
SCAMP registers ....................5/10
Apricot ports...........................5/11
Hard disk drive controller
registers.................................... 5/14
Serial port controller
registers.................................... 5/14
Ethernet controller................ 5/15
Business audio......................... 5/17
Floppy disk controller ...........5/17
Parallel port controller .........5/18
Video DAC ..............................5/19
VGA registers .........................5/20
CL-GD542X Extension
registers.................................... 5/25
Chapter 5 Chapter 3
2 LS PRO HARDWARE TECHNICAL REFERENCE
APPENDICES
A: Specifications
B: Revision C system board
C: Error beep codes
INDEX
INTRODUCTION
Chapter 1
Contents
1 INTRODUCTION
General........................................1/2
Variants........................................1/2
System unit .................................1/3
Introduction
Keyboard.....................................1/3
Monitors......................................1/3
Expansion ....................................1/4
Contents
Chapter 1
Chapter 1
Chapter 3
Chapter 3
Chapter 5
LS PRO HARDWARE TECHNICAL REFERENCE 1/1
Chapter 6
Introduction
General
Contents
Chapter 1
Chapter 1
The Apricot LS Pro family is a range of ultra-compact IBM compatible computers which
can be used as a personal computer, a network workstation or a high resolution
graphics workstation.
The main features of the system are:
• 80386SX or 486SLC microprocessor operating at up to 33MHz.
• 2 to 16 Mbytes of on-board RAM.
• IBM compatible serial port.
• IBM compatible parallel port.
• Ethernet port.
• Token-Ring port (optional).
• PS/2 compatible mouse port.
• Floppy disk controller on system board.
• Hard disk connector on system board.
Chapter 3
Variants
Chapter 5Chapter 6 Chapter 3
• Full IBM functional compatibility.
• On-board VGA.
• On-board high resolution video.
• Internal power supply.
• LOC Technology security sub-system.
• Socket for 80387SX.
• Windows 3.1 compatible Business Audio subsystem.
The basic system unit may be fitted with:
• 2 to 16 Mbytes of RAM.
• 80, 120, 170, 240 or 540 Mbyte hard disk drive.
• 3.5 inch floppy disk drive.
• 80387SX coprocessor.
A VGA monitor will be required. To take advantage of the high resolution video modes
a suitable SVGA or EVGA monitor will be required.
1/2 LS PRO HARDWARE TECHNICAL REFERENCE
System unit
Introduction
The system unit contains: the processor(s), the system memory, disk drives, power
supply, security circuitry and interfaces to keyboard, monitor and peripherals. All the
interface circuitry except the Token-Ring network interface is on the system board.
Contents
Keyboard
Monitors
Dedicated connectors are provided on the system board for a Token-Ring module.
A block diagram of the system unit is shown at the end of this section. It shows the
components of the system and identifies functions implemented on the system board.
The keyboard is a full QWERTY typewriter keyboard and numeric keypad together
with editing keys. The layout of the 102 key UK keyboard is compatible with the IBM
AT enhanced keyboard.
The keyboard is fitted with a PS/2 style miniature DIN connector and any fully
compatible keyboard can be plugged into the system unit.
The system board is fitted, with a VGA video interface which will drive any suitable
monochrome or colour analogue monitor.
The on-board VGA controller also supports high resolution video modes. To take
advantage of the higher resolution video modes an SVGA or EVGA monitor must be
used. Video drivers for popular software packages are available.
Chapter 1
Chapter 1
Chapter 3
Chapter 3
Chapter 5
Chapter 6
LS PRO HARDWARE TECHNICAL REFERENCE 1/3
Introduction
Expansion
System RAM may be expanded to 16 Mbytes by fitting SIMMs.
Contents
Chapter 1
Chapter 1
A socket for an 80387SX coprocessor is fitted on the system board.
MONITOR
AC
INLETACOUTLET
POWER
SUPPLY
HARD DISK DRIVE
NETWORK
PORTS
FAN
VIDEO
PORT
PROCESSOR; MEMORY; VIDEO ADAPTER
ETHERNET CONTROLLER; SERIAL PORT
PARALLEL
PORT
SYSTEM BOARD
PARALLEL PORT;
LOC TECHNOLOGY SECURITY
FLOPPY DISK CONTROLLER;
HARD DISK CONNECTOR;
KEYBOARD AND MOUSE PORTS;
BUSINESS AUDIO.
FLOPPY DISK DRIVE
PORTS
including:
SERIAL
MOUSE
PORT
KEYBOARD
PORT
AUDIO
PORTS
Chapter 3
Chapter 5Chapter 6 Chapter 3
KEYBOARD
MOUSE
1/4 LS PRO HARDWARE TECHNICAL REFERENCE
SYSTEM UNIT
Chapter 2
Contents
2 SYSTEM UNIT
Introduction................................2/2
External layout...........................2/2
Internal layout ............................2/3
Servicing level.............................2/3
Dismantling and re-assembly . 2/3
Warnings and cautions........ 2/3
Antistatic precautions.......... 2/4
Equipment required ............. 2/4
System board connectors... 2/4
Removing the system unit top
cover ........................................2/5
Removing the system board
metalwork...............................2/6
Removing the floppy drive.. 2/7
Removing the power supply
metalwork...............................2/8
Removing the hard disk
drive..........................................2/9
Removing the fan................ 2/10
Removing the power
supply .................................... 2/11
Removing a Token-Ring
module .................................. 2/11
System unit
Removing a parallel port
cable ...................................... 2/13
Removing a thick wireEthernet
assembly ............................... 2/13
Removing the system
board ..................................... 2/13
Removing an escutcheon
plate....................................... 2/14
Removing the power switch
linkage ................................... 2/14
RFI screening tray and
insulation sheet ................... 2/15
Installing add-ons .................... 2/16
Memory upgrades............... 2/16
Installing an 80387SX......... 2/19
System unit connectors ........ 2/20
VGA....................................... 2/20
Ethernet................................ 2/20
Serial port............................. 2/21
Parallel port ......................... 2/22
Keyboard/mouse
connectors ........................... 2/22
Contents
Chapter 2
Chapter 2
Chapter 2
LS PRO HARDWARE TECHNICAL REFERENCE 2/1
Chapter 5
Chapter 6
System unit
Introduction
The main components of the system unit are:
Contents
Chapter 2
External layout
Chapter 2
• base
• top cover
• system board
• disk drives
• power supply
The top cover is easily removed without any tools.
The system board contains all the processing and interface circuitry and the system
RAM. 2 or 4 Mbytes of RAM is soldered to the board and SIMMs can be fitted to increase
the total amount of system RAM to a maximum of 16 Mbytes.
The front panel of the system unit contains: the power switch and slots for four LEDs
and the IR detector for the security card. The right side panel contains the keyboard
and mouse ports, and the audio input and output sockets.
POWER SWITCH
Chapter 2
Chapter 5
Chapter 6 Chapter 3
MOUSE
KEYBOARD
AUDIO IN
AUDIO OUT
INFRARED
SENSOR
LAN
INDICATOR
FLOPPY DISK
INDICATOR
HARD DISK
INDICATOR
POWER
INDICATOR
FLOPPY
DISK DRIVE
The floppy drive bezel is on the right side of the system unit.
The rear panel contains the following connectors: mains power input; auxiliary power
outlet; monitor; Ethernet ports; serial port; parallel port.
The layout of the rear panel is shown in the illustration below.
PARALLEL
PORT
SERIAL
PORT
SECURITY
LOOP
VIDEO
PORT
TWISTED
PAIR ETHERNET
THICK
ETHERNET/
TOKEN RING
PORT
COVER
LOCK
THIN
ETHERNET
PORT
POWER
OUT
POWER
IN
Illustrations and pinouts of the connectors on the rear panel are given at the rear of
this section.
2/2 LS PRO HARDWARE TECHNICAL REFERENCE
Internal layout
SYSTEM BOARD
METALWORK
FLOPPY
DRIVE
HARD DISK
DRIVE
POWER
SUPPLY
System unit
The layout of the inside of the system unit is shown in the illustration below. At the front
left of the system unit is the hard disk drive. Behind the hard disk drive is the power
supply unit. Both the power supply and the hard disk drive are beneath a metal cover.
Contents
Servicing level
The floppy drive is at the front right of the system unit attached to a metal plate which
extends the full length of the system board.
The level of information in this section is intended to enable suitably qualified personnel
to remove and replace major components of the system unit and to access components
to install add-ons.
Chapter 2
Chapter 2
Chapter 2
Dismantling and re-assembly
The LS Pro range has been designed to meet international EMI and safety standards.
Warnings and To ensure safety and continued compliance with these standards, observe the
cautions following precautions.
• It is recommended that modifications are carried out by an authorized dealer.
Unqualified users should not normally dismantle the equipment.
• Replacement parts should be of the type and rating specified by the manufacturer.
• All earth connections must be maintained to the original specification.
• Ensure that all personnel concerned are familiar with the action to be taken in
the event of electric shock.
Warning
Never carry out any work on the equipment with power applied. Always switch off at the mains
and remove the power lead from the equipment before starting work.
Note
Any reference to left or right during dismantling and re-assembly assumes that the reader is
viewing the unit from the front, unless otherwise stated.
Chapter 5
Chapter 6
LS PRO HARDWARE TECHNICAL REFERENCE 2/3
Contents
System unit
Antistatic All electronic components and equipments are sensitive to static electricity. Even
precautions small electrostatic discharges can render components useless or severely shorten
their working life, therefore preventive measures should always be taken.
No work should be carried on any item unless it is in a Special Handling Area (SHA)
as defined in BS CECC 00015:Part 1. In general this involves:
• a common earth point
• an earthed bench or bench mat
• an earthed wrist strap
Chapter 2
Chapter 2
Chapter 2
Equipment The following tools are required to dismantle the system unit.
required
• Philips screwdriver
• Flat-bladed screwdriver
• Nut spanner set
• thin nosed pliers
System board Many of the dismantling/reassembly procedures which follow involve the
connectors disconnection and reconnection of system board plugs and sockets. The following
table gives, for each socket, the connector number which identifies it. This number
is printed on the system board next to each connector.
Connector Label
Parallel port PL8
Token ring module PL9 and PL16
Hard disk drive power PL12
Thick Ethernet PL13
System board power PL15
Hard disk drive control PL17
Floppy disk drive PL18
Loudspeaker PL40
Chapter 5
Chapter 6 Chapter 3
2/4 LS PRO HARDWARE TECHNICAL REFERENCE
THICK
ETHERNET
ASSEMBLY
TOKEN RING
MODULE
SW 1
BATTERY
POWER
JUMPER
POWER
TOKEN RING
MODULE
System unit
PARALLEL
PORT
CABLE
Contents
Chapter 2
Chapter 2
HARD DISK
SIGNAL
FLOPPY
DISK
HARD DISK
POWER
LOUDSPEAKER
Removing the A keylock on the rear panel of the system unit locks the top cover in place. The
system unit cover cannot be removed unless this is unlocked. The cover is located by a ledge at
top cover the front and lugs on the sides and at the rear. Two thumbscrews in the rear panel
secure the cover.
Chapter 2
Chapter 5
LS PRO HARDWARE TECHNICAL REFERENCE 2/5
Chapter 6
System unit
The following illustration shows the thumbscrews and keylock.
Contents
Chapter 2
Chapter 2
CASING
SCREWS
COVER
LOCK
CASING
SCREWS
1. Check that the system unit power switch and mains supply are switched off and
disconnect the mains supply.
2. Ensure that the keylock on the rear panel is unlocked.
3. Loosen the two thumbscrews at the top of the rear panel. If they have been done
up tightly it may be necessary to use a screwdriver to loosen them.
4. Slide the top cover forward a few millimetres and lift it clear.
5. Replacing the top cover is simply the reverse of removal. Check that the keylock
is in the unlocked position. Make sure that the top cover is properly aligned
during replacement and do not force it into position.
Note
It is not necessary to remove cables (other than the mains power cable) to remove the system
unit top cover. However, in order to remove some of the internal components external cabling
must be removed.
Chapter 2
Chapter 5
Removing the The system board metalwork is secured to the power supply metalwork by lugs, and
system board by clips to the system unit base.
metalwork
SECURING
LUGS
SECURING
CLIPS
1. Remove the system unit top cover.
2. Release the two retaining latches. On releasing the latches, the system board
metalwork will spring up slightly.
Chapter 6 Chapter 3
2/6 LS PRO HARDWARE TECHNICAL REFERENCE
System unit
3. Hinge the system board metalwork to the vertical as shown below:
4. Disconnect the loudspeaker cable from the system board.
5. If your system is fitted with a floppy disk drive disconnect the ribbon cable at the
system board taking care not to strain the cable or its connectors.
Contents
Chapter 2
Chapter 2
Chapter 2
6. Lift the system board metalwork clear of the computer.
7. Invert the system board metalwork, and rest it on a flat surface.
8. Replacement is simply the reverse of removal. Take care to ensure that the
metalwork engages correctly. Do not use undue force. Route the loudspeaker
cable between the front of the system unit and the LEDs.
Removing the The floppy drive is mounted in the metalwork above the system board.
floppy drive
Two variants of metalwork have been used, they are both shown in the illustration
below.
Chapter 5
Chapter 6
LS PRO HARDWARE TECHNICAL REFERENCE 2/7
System unit
1. Remove the system board metalwork.
2. Remove the four screws which secure the floppy drive and remove the drive.
Contents
Chapter 2
Chapter 2
3. Replacing the floppy drive is simply the reversal of removal. If the drive being
installed is a replacement ensure that the drive select switch on the side of the
drive is in the same position as that on the old drive.
Removing the The power supply metalwork covers the top of the power supply and divides the
power supply system unit, it applies gentle pressure to the top of the system unit fan. The system
metalwork board metalwork uses the power supply metalwork for location.
The power supply metalwork is secured by two screws and a number of lugs.
SECURING
SECURING
LUGS
SCREW
FAN LOCATION
SLOT
EARTH
BOND
SCREW
Chapter 2
Chapter 5Chapter 6 Chapter 3
SECURING
LUGS
1. Remove the system board metalwork.
2. Remove the earth bond screw which secures the system board escutcheon plate
to the power supply metalwork.
3. Remove the screw in the rear panel between the mains inlet and outlet which
secures the power supply metalwork.
4. Slide the power supply metalwork forward by approximately 6mm to free the
lugs.
5. An earth cable connects the power supply to the metalwork. Gently lift the
metalwork and carefully turn it over.
6. Remove the screw which secures the cable to the metalwork and lift the
metalwork clear.
2/8 LS PRO HARDWARE TECHNICAL REFERENCE
System unit
7. Replacement is the reverse of removal. However care must be taken to note the
following:
Warning
Contents
Remember to reconnect the power supply earth cable to the metalwork.
• The metalwork must be behind the switch operating lever of the power switch
linkage.
• A metal RFI screening tray is fitted in the base of the system unit. During the
replacement of the power supply metalwork the front edge of the tray can be
damaged.
In order to prevent damage occurring use a piece of card to hold down the
fingers at the front edge of the metalwork while the metalwork is replaced.
Once the metalwork is in place gently remove the card.
• Take care to ensure that the lugs on the bottom right of the metalwork are
properly engaged and that the metalwork does not foul on the fan.
The fan rests on a flexible foam pad which is compressed when the power
supply metalwork is in place. A slot is provided in the metalwork to allow a
small blunt instrument (flat bladed screwdriver) to push the fan down during
the replacement of the metalwork. Do not force the power supply metalwork
into position.
Removing the The hard disk drive is attached to the system unit base by four screws on the
hard disk drive underside of the system unit. The following illustration identifies the screws which
hold the hard disk drive in place.
Chapter 2
Chapter 2
Chapter 2
Chapter 3
HARD DISK
DRIVE
SECURING
SCREWS
1. Remove the system unit top cover, system board metalwork and power supply
metalwork.
2. Disconnect the hard disk drive power and signal cables from the system board.
Warning
Do not attempt to disconnect the cables from the drive with the drive still in the system
unit. Attempting to do so will damage the drive circuit board.
Chapter 5
Chapter 6
LS PRO HARDWARE TECHNICAL REFERENCE 2/9
System unit
Contents
Chapter 2
3. Holding the hard disk drive firmly in position carefully turn the system unit onto
one side and remove the four screws which secure it.
HARD DISK
DRIVE
Chapter 2
Chapter 2
Removing the fan The cooling fan rests on a flexible foam pad and is located in the base of the system unit
4. Still holding the disk drive, carefully turn the system unit back and rest it on the
work surface.
5. Slide the hard disk drive to the right to clear the power supply metalwork and
lift the hard disk drive out of the system unit complete with the power and signal
cables.
6. Replacing the hard disk drive is simply the reverse of removal. If the drive being
installed is a replacement ensure that the drive select jumpers are in the same
positions as those on the old drive.
Warning
1. Reconnect the power and signal cables to the drive before putting the drive in
position.
2. Ensure that the screws which you use to secure the drive are the ones which you
removed. If you use longer screws you will damage the drive.
by small ribs. Gentle pressure from the power supply metalwork ensures that the fan
is held in place.
1. Remove the power supply metalwork.
Chapter 5Chapter 6 Chapter 3
2/10 LS PRO HARDWARE TECHNICAL REFERENCE
2. Disconnect the fan power connector from the PSU.
3. Remove the fan.
4. Replacement is simply the reverse of removal. Make sure that you replace the
fan in the same orientation as it was before removal, and that the fan power cable
is secured to the fan with a cable tie.
System unit
SECURING
SCREWS
Removing the The power supply is secured to the bottom of the system unit by four screws. The
power supply following illustration identifies the screws that must be removed and the connectors
that must be disconnected in order to remove the power supply.
1. Remove the power supply metalwork.
Contents
Chapter 2
Chapter 2
2. Disconnect the system board and fan power connectors.
3. Lift out the fan.
4. Remove the four screws securing the power supply.
5. Lift the power supply clear of the system unit.
6. Replacement is simply the reverse of removal. Ensure that the voltage range
selection jumper is in the correct position for the mains supply available. The
jumper is identified in section 4 of this manual.
Removing a The Token-Ring module is secured to three standoff pillars inside the system unit,
Token-Ring and to the escutcheon plate at the rear of the system unit. To remove the module
module follow the instructions below:
1. Remove the system board metalwork.
2. Remove the screw in the rear panel of the system unit, to the right of the TokenRing connector.
TOKEN RING
CONNECTOR
Chapter 2
Chapter 3
Chapter 5
SECURING
SCREW
LS PRO HARDWARE TECHNICAL REFERENCE 2/11
Chapter 6
System unit
3. Remove the screws and nuts which secure the module to the standoff pillars.
Contents
Chapter 2
Chapter 2
SECURING
NUTS
4. Gently remove the module.
Note
Care must be taken to ensure that the module is removed vertically. Any horizontal
movement will damage the connectors.
SECURING
SCREW
Chapter 2
Chapter 5Chapter 6 Chapter 3
Read the following paragraphs before replacing the module.
The Token-Ring module connectors have three components: the connectors on the
system board, the connectors on the Token-Ring module, and the pin assemblies which
connect them. When you remove the Token-Ring module the pin assemblies will
probably come out with the Token-Ring module, although they may remain in the
system board.
When the Token-Ring module is in position the plate that surrounds the Token-Ring
connector is between the system unit base and the escutcheon plate. The two standoff
pillars by the connector nearest the power supply, protrude through corresponding
holes in the Token-Ring module.
It is vital that during replacement the Token-Ring module is correctly aligned. Any
misalignment will damage the connectors and/or the module. When replacing the
module make sure that the plate is inserted correctly and that the standoff pillars are
correctly aligned. Check that the connectors are correctly aligned, then gently insert
the module.
Warning
Take care not to exert undue pressure when inserting the module.
2/12 LS PRO HARDWARE TECHNICAL REFERENCE
System unit
Removing a The parallel port cable is secured to the escutcheon plate by the two D-type
parallel port connector screwlocks. To remove the cable:
cable
1. Remove the system board metalwork.
Contents
2. Remove the two screwlocks in the parallel port connector.
3. Unplug the cable from the socket on the system board and lift the cable clear.
4. Replacement is simply the reverse of removal.
Removing a thick The thick wire Ethernet assembly is secured to the escutcheon plate at the rear of
wire Ethernet the system unit. To remove the assembly follow the instructions below:
assembly
1. Remove the system board metalwork.
2. Remove the screw that secures the thick wire Ethernet assembly to the
escutcheon plate, unplug the assembly cable from the system board, and lift the
assembly clear of the system unit.
3. Replacement is simply the reverse of removal.
Removing the The system board is secured to the base of the system unit by seven screws through
system board the system board and four screwlocks through the escutcheon plate. The following
illustration identifies the positions of the system board screws.
SECURING SCREWS
Chapter 2
Chapter 2
Chapter 2
SECURING SCREWS
1. Remove the system unit top cover and put the system cover lock in the locked
position.
2. Remove the system board metalwork and disconnect all system board connectors.
3. Remove the parallel port cable and thick cable Ethernet assembly or Token-Ring
module (if fitted).
4. Remove the seven screws which secure the system board.
5. Remove the screwlocks that secure the video and serial port connectors.
6. Remove the lock nut on the thin Ethernet connector.
7. Carefully lift the system board clear of the system unit.
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Chapter 6
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System unit
Contents
Chapter 2
escutcheon plate the rear of the system unit base. To remove the escutcheon plate:
Notes
1. If the system cover lock is not in the locked position the system board will foul during
removal.
2. During removal the audio connector may foul on the RFI isolation tray. If so, press
the isolation tray against the side of the system unit base to allow the connectors
clearance.
7. Replacement is simply the reverse of removal.
Ensure that all the switches and jumpers on a replacement board are in the correct
position.
Removing an The escutcheon plate at the rear of the system unit is secured by three screws to
1. Remove the system board metalwork.
2. Remove the system board.
Chapter 2
Chapter 2
3. Remove the screw that secures the escutcheon plate to the power supply
metalwork.
4. Remove the three screws that secure the escutcheon plate to the system unit,
and lift the escutcheon plate clear.
5. Replacement is simply the reverse of removal.
Removing the The power switch linkage mechanically links the system ON/OFF switch on the front
power switch of the system unit to the power supply ON/OFF switch. It is located in two slots in the
linkage system unit base plastics. The linkage must clear a rib on the side of the base plastics
during removal, and another during replacement. To remove the linkage:
REAR
SLOT
POWER SWITCH
LINKAGE
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FRONT
SLOT
SPRING
RIB
OPERATING
LEVER
1. Remove the system unit top cover, system board metalwork, hard disk drive,
power supply metalwork, fan, power supply and system board.
Warning
During the following instructions do not apply excessive pressure or the linkage may
be deformed or the plastics break.
System unit
2. Using a pair of thin nosed pliers, disconnect the spring and put it somewhere safe.
3. Exerting gentle inward pressure on the operating lever, slide the power switch
linkage forward past the rear of the two ribs, far enough to free the back of the
linkage from the rear slot.
Contents
4. Slide the linkage back bending it gently to allow it to pass to the right of the rear
slot and push it as far back as it will travel.
REAR
SLOT
OUTWARD
POWER SWITCH
LINKAGE
INWARD
SPRING
FRONT
SLOT
RIB
OPERATING
LEVER
5. With the 90° bend at the front of the linkage against the front of the two slots
swing the rear of the linkage into the centre of the system unit.
Chapter 2
Chapter 2
Chapter 2
Note
There should be no resistance to this movement. If there is resistance you have not
pushed the linkage far enough back.
6. Slide the linkage back through the slot and lift it clear.
7. Replacement is simply the reverse of removal except that gentle inward pressure
must be exerted to the front of the linkage to allow it to pass the front rib. Do
not force the linkage into place.
RFI screening tray The LS Pro system unit base is fitted with a metal RFI screening tray and a plastic
and insulation insulation sheet during manufacture. The metal tray reduces RFI emissions from the
sheet system unit and ensures compliance with international regulations.
The plastic sheet insulates components inside the system unit from the RFI
tray. Both components are essential.
There should never be any need to remove the tray or the screening sheet.
However if you do need to remove them you must ensure that they are
replaced correctly when you reassemble the system.
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Chapter 5
Chapter 6
LS PRO HARDWARE TECHNICAL REFERENCE 2/15
Contents
System unit
Insulation sheet
The plastic insulation sheet rests on the isolation tray and is not secured until the other
system unit components are installed. Correct positioning of the sheet can be ensured
by checking that the screw holes in the sheet align with those in the RFI tray, and the
system unit base.
RFI screening tray
The RFI screening tray sits in the system unit base, it is only secured by double sided
tape at the front left of the system unit, in front of the hard disk drive.
Chapter 2
Installing add-ons
Chapter 2
Chapter 2
Chapter 5Chapter 6 Chapter 3
Since the tray includes cut-outs for all the system unit connectors, the correct
orientation should be obvious. Ensure that the connector cut-outs and the screwholes
in the base of the tray are all correctly aligned with the system unit base. Then secure
the front left edge of the tray with the double-sided tape.
Memory During manufacture 2 or 4 Mbytes of RAM can be soldered to the system board.
upgrades System board memory can be expanded to a maximum capacity of 16 Mbytes by
fitting SIMMs in sockets provided on the system board.
When 4 Mbytes of RAM is installed during manufacture four SIMM sockets are fitted.
When 2 Mbytes of RAM is installed six SIMM sockets are fitted.
SIMMs must be installed in pairs, upgrades of 2 and 8 Mbytes are available. The 2 Mbyte
upgrade contains two 60nS 1Mx9 SIMMs, the 8 Mbyte upgrade contains two 60nS 4Mx9
SIMMs.
The following table identifies the valid upgrade combinations.
System board Upgrade
(Mbytes) (Mbytes)
2 4 2 - 2 6 2 2 2 8 2 2 2 1
2 12 2 8 2 16 - 8 8 2
4 6 N/A 2 4 8 N/A 2 2 1
4 12 N/A 8 4 16 N/A 8 8 2
1 2 3
Bank
Notecapacity to
Notes
1. For both system board RAM capacities an alternative method of achieving 8 Mbytes
of RAM is to install an 8 Mbyte upgrade in bank 2 and leave the other bank (or banks)
empty. This configuration disables the RAM soldered to the system board.
2. When banks 2 and 3 are both occupied by 8 Mbyte upgrades the RAM soldered to the
system board is disabled.
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