Service manual

What to do next
Once you have repaired a fault and the computer is
functioning, we recommend that you use the test
software described in the following section entitled
Checking a partly working computer, to check for and
correct any other faults.
Checking a partly working
computer
The following section gives details of how to isolate
faults to individual modules, using the test disc (0292,
824) on machines which are running, but exhibiting
faults. The test software can be used in two ways:
• As a test suite, including all the tests that you need for
a standard configuration machine. The tests run
automatically and in sequence.
• As individual tests to test an individual module.
We suggest that if the description of a fault is specific to
a module then you only need to run the appropriate
individual test. Once you have determined the area of
the fault and repaired it, make sure that you run the full
test suite on the working computer before returning it to
the customer.
The flowchart on the next page, Figure 1-2: Procedure to
check a partly working computer shows you how to
diagnose and repair a partly working computer.
Before the tests
Before you run the test software suite, you need to
perform the following tasks:
• back up the test disc
• validate the test equipment
• create a test IDE hard disc
• replace the customer's hard disc
• connect the customer's equipment
• save the customer's CMOS RAM settings
• create a CMOS test data file
• check the memory size of the computer
Safety considerations
Some of the tasks described in this section require that
you remove the top cover of the Archimedes computer.
Although the PSU is designed to comply with
BS7002/EN60950 Class 1, you must still take care to
ensure that no metal objects fall (or are put) into the
PSU through the ventilation holes.
Notes:
1 You must only connect the power after you have
made all the other connections.
2 You must switch off the equipment and disconnect
from the mains supply before removing any other
connections.
You will find instructions for removing the top cover in
Part 2 - Disassembly and assembly.
Backing up the test disc
Before you start testing, make a backup copy of the test
disc (0292,824). You will need the following equipment:
• a known working A5000 computer plus keyboard and
monitor.
• test disc to be copied (source disc).
• floppy disc already formatted (destination disc).
Follow the procedure given below to make a backup
copy of the test disc:
1 Start-up the computer so that it displays the desktop.
Note if the desktop is not displayed on start-up type:
*DESKTOP <return>
at the • prompt.
2 Ensure the test floppy disc is write protected, then
insert the test floppy disc into the disc drive.
3 Open the directory window on the floppy disc by
pressing the left hand mouse key while the mouse
pointer is over the floppy disc icon.
4 Execute the ! MakeACopy program by pressing the
left hand mouse key twice while the mouse pointer is
over the !MakeACopy icon in the directory window.
5 You are asked whether you are sure that you want to
back up the test disc. Reply 'y' if the test disc is write
protected.
6 Press the space bar when prompted.
7 Insert the destination disc when prompted.
8 When the program has finished, turn off the monitor
and computer.
Validating the test equipment
Before carrying out any of the tests in this chapter,
validate the test equipment. To do this, follow the
procedures given in this section, substituting a known
working unit for the customer's unit.
If the test equipment fails, you should repair the test
equipment and retest on a known working unit.
1-4 Issue 1, November 1991 Part 1- Fault diagnosis and repair