Mitsubishi Electric Apricot User manual

apricot
Qi 486
ADD-ON INSTALLATION GUIDE
MITSUBISHI ELECTRIC

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doesnot represent a commitment on thepart of Apricot Computers Limited. The
softwaredescribedinthis manual is furnished under a license agreement. The
software may be used or copied only in accordance with the terms of this
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Copyright©ApricotComputersLimited1992
Publishedby
ApricotComputersLimited
3500Parkside
BirminghamBusinessPark
B377YS
MITSUBISHIELECTRIC
PrintedintheUnitedKingdom
Partno.15007631

1
Contents
Introduction 2
Anti-static precautions 3
Installing extra memory 4
Installing an 80487SX in Qi 486SX 11
CPU module upgrades 18

2
Introduction
This guide contains instructions on installing extra memory
in Qi 486 and 486SX, and an 80487SX coprocessor in a
Qi 486SX. This document should be your only source of
information when installing extra memory or a
coprocessor.
You should read this document before purchasing extra
memory or a coprocessor. If, having read the relevant
instructions, you are not confident about installing the
upgrade, you may wish to have your supplier or service
organisation install it for you.
Warning
Never carry out any work on the computer with power
applied. Always switch off at the mains and remove the
power lead from the system unit before starting work.
Before you start installing the upgrade you should be
thoroughly familiar with all the relevant instructions in this
guide and the appropriate sections of your
Owners
Handbook
.
CPU module upgrade
The system boards in Qi 486SX and Qi 486 have
removable CPU modules. These modules can be removed
and replaced without replacing the entire system board.
80486SX CPU modules can be removed and replaced
with a CPU module fitted with an 80486DX. This upgrade
is not user installable. Contact your supplier or service
organization for details.

3
Anti-static precautions
All electronic components and equipments are sensitive to
static electricity. Even small electrostatic discharges can
render components useless or severely shorten their
working life, therefore you should always take preventative
measures.
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

4
Installing extra memory
The system board in your computer has eight sockets for
Single Inline Memory Modules (SIMMs). The system board
treats these sockets as two sets of four. Each set of four
sockets must either be all occupied, or all empty. SIMMs
are supplied in sets of four.
How much memory
Three different capacities of SIMM are available:
256kbyte, 1Mbyte and 2Mbyte, giving upgrade kit
capacities of 1, 4 and 8 Mbytes. The system board does
not support all possible combinations of these three
capacities. The following table shows the RAM capacities
supported:
Memory Fitted SIMM Capacity
Set 0 Set 1
1 Mbyte 256k -
2 Mbyte 256k 256k
4 Mbyte 1M -
5 Mbyte 256k 1M
8 Mbyte 1M 1M
12 Mbyte 2M 1M
16 Mbyte 2M 2M
If you do not know how much memory is fitted to your
system, you can find out when you switch your computer
on. During the power up sequence on-board memory is
tested and the capacity is displayed on the screen.
On the start up screen two memory capacities will be
shown: base and extended. By adding the base and
extended memory capacities together and dividing by
1024 you will arrive at the amount of RAM (in Mbytes)
fitted to your system board. The result should always be
an integer.
If the result of the calculation is not an integer you
probably have ROM BIOS shadowing enabled and you
should add 384kbytes to the total you arrived at before
dividing by 1024.

5
The following diagrams show which type of SIMM should
be fitted in each slot for each possible memory capacity.
The memory sockets are labelled ‘MM1’ to ‘MM8’, note
that the sockets are not numbered in sequence.
TOWARDS REAR OF MACHINE TOWARDS REAR OF MACHINE
TOWARDS REAR OF MACHINE TOWARDS REAR OF MACHINE
256 KBYTE MODULES
1 MBYTE MODULES256 KBYTE MODULES
Orientation 1 Mb
2 Mb 4 Mb
MM4 MM8 MM3 MM7 MM2 MM6 MM1 MM5

6
TOWARDS REAR OF MACHINE TOWARDS REAR OF MACHINE
TOWARDS REAR OF MACHINE TOWARDS REAR OF MACHINE
1 MBYTE MODULES
2 MBYTE MODULES2 MBYTE MODULES
5 Mb 8 Mb
12 Mb 16 Mb
1 MBYTE MODULES
256 KBYTE MODULES
1 MBYTE MODULES

7
Obtaining access
The SIMM sockets are accessible with the system unit
cover removed. To obtain access:
1. Take suitable anti-static precautions.
2. Remove the system unit cover as described in your
Owner’s Handbook .
3. Identify the SIMM sockets from the illustration
below.
SWITCHES
SIMMS

8
Removing and replacing SIMMs
If you are fitting additional SIMMs remove those already
installed.
Removing SIMMs
Starting with the SIMM nearest the front of the system unit
and working towards the rear:
1. Note which socket the SIMM is in.
2. Lever the metal clips on each side of the socket
gently away from the SIMM using your thumbnails.
When the clips are far enough apart the top edge
of the SIMM will move forward until the SIMM is at
an angle of about 15°.
3. Taking care to avoid touching any of the
components on the SIMM grip the top corners of
the SIMM between thumb and first finger and
carefully pull the SIMM out of the socket.
4. Repeat steps 1 to 3 for all the other SIMMs.