LOCATING THE SOCKETS ON THE BOARD
Position the machine so that you are facing the front. The sockets will then be located halfway along the
right-hand side of the main printed circuit board. They are labelled: IC24, IC25, IC26 and IC27. See
diagram
on
separate sheet.
Note: If you have any Podules installed you will need to remove them in order to gain access to
the ROM sockets.
REMOVING THE OLD ICs
You must remove the existing ICs in sockets IC24, IC25, IC26 and IC27. To do this, take an IC extraction
tool or a flat-bladed screwdriver and gently prise up each end of the IC, a bit at a time.
It is important that you remove the ICs extremely gently otherwise you may bend the pins or damage the
sockets. If you are using a screwdriver, be careful not to catch the ribs of the sockets.
IDENTIFYING THE ICs
The upgrade kit consists of four ROMs. The way in which the ICs are labelled and their appearance
depends on the manufacturer. Before inserting the ICs it is important to clearly identify the type of ICs you
are supplied with.
Using the table below, identify which IC is which by examining the markings on them.
ROM
Markings
Markings
1
0277,022
MB831000-20P-700
2
0277,023
MB831000-20P-701
3
0277,024
MB831000-20P-702
4
0277,025
MB831000-20P-703
You may find it easier when you come to install the ICs if you make a note of which IC is ROM 1, ROM 2
and so on.
The ICs will be one of two types. These either have a distinctive semi-circular notch at one end of the IC or
a long groove down one side.
2
