Service manual

Service Manual
Individual tests
You can choose which tests you run from this section —
they are not all run automatically in sequence. They are
for testing an individual module or expansion card. So
you have two options:
• You can run any one of the tests described in the
section entitled Main PCB functional test suite on
page 4-7 by itself.
See that section for a description of each module test.
• You can run any one or more of the individual
expansion card tests described in the remainder of
this chapter.
Run the relevant expansion card test detailed below; if it
fails, substitute a known good expansion card. If the test
still fails, substitute a known good backplane. If the test
fails again, either replace the main PCB, or repair it. For
expansion card details, see the relevant user guide
supplied with the card.
Note: Expansion cards were previously known as
Podules.
Additional equipment required
Refer to the section entitled Additional test equipment
required when testing expansion cards on page 4-1. It
lists the extra equipment you need for each test.
Preparing to run the individual
expansion card tests
The tests alter the contents of the battery backed RAM
that holds the computer's configuration data.
1 Make sure you have followed the instructions in the
section entitled Preparing to run the tests on page 4-5.
2 Select the Individual tests option.
Another menu is then displayed.
3 Select the Exp.-Cards option.
(The other option — Pcb-Module — is for when you want
to test just one particular main PCB module at a time.)
You will now see part of a list of test options. To see the
rest of the options, press the space bar.
ROM expansion card test
Carry out this test whenever you install, repair or replace
a ROM expansion card.
Note: These instructions assume that both the expansion
card and the backplane have already been correctly
installed.
Connect up the equipment
It is important to connect the equipment to the computer
in the correct order:
• Ensure the ROM Expansion card test ROM (
0276,230-01) is fitted to socket IC6, and set the
following links:
• LK1-6 to position C
• LK2-6 to position A.
• Ensure the EPROM FS (0276,221) is fitted to IC
socket 1, and set the following links:
• LK1-1 to position A
• LK2-1 to position C.
• Connect the keyboard to the front panel connector
• Connect the monochrome monitor to the Mono Video
socket, or analogue RGB monitor to the Analogue
RGB socket
• Connect the monitor to the mains supply (don't switch
on yet)
• Connect the computer to the mains supply (don't
switch on yet).
Run the test
1 Follow the instructions in the section entitled Preparing
to run the individual expansion card tests on page 4-
15.
2 Press the relevant key to select the ROM expansion
card test.
The display will then clear and the selection will be
displayed.
The test will then run. When the test is finished a
message is displayed to tell you whether the ROM
expansion card has passed or failed.
You have now completed the ROM expansion card tests.
Follow the instructions in the section entitled Completing
the tests on page 4-6.
Remove the test ROM and reset links LK1-6 and LK2-6.
Part 4 - Fault diagnosis Issue 2, June 1991 4-15