Service manual

Archimedes Field Change Orders
Two Archimedes Field Change Orders will shortly be issued for the modification of a number of
Archimedes that show problems in the field.
FCO E008 relates to a modification which you may have seen implemented in recent production computers -
the addition of an electrolytic capacitor soldered between two of the pins of IC68. This modification reduces
the spurious noise found on the audio signal through the loudspeaker. We will advise more details shortly,
including a work instruction, serial number range, credit rates etc. This information will be sent to all
authorised Archimedes Repair Centres. Generally, it will be possible to perform this in conjunction with
FCO E009, when this is required.
FCO E009 will only be necessary when the Archimedes is required to be used with certain types of
multisync monitor. Again, the modification is being put into new production machines, but the upgrade is
quite simple, involving removing one resistor, and replacing a couple of other ones. However, due to the
problems inherent with removing components from four-layer boards, it is advised that only service agents
with vacuum desoldering equipment actually desolder components from the board. An acceptable alternative
would be to crop the wires to the components concerned, and in those requiring replacement, soldering the
new resistor leads to the remaining legs of the removed resistors. Again, details of this upgrade will be
provided shortly to authorised Archimedes Repair Centres.
Finally, on the subject of Field Change Orders, thank you to all those involved in the recent FileStore
upgrade. After a hiccup with the supply of ROMs, all went very smoothly.
Disc Compatibility and Transferring Software to the Archimedes
The Archimedes will read three different formats of ADFS disc. The first is a 320k format (single sided 80 track),
which is compatible with Master and Compact ADFS, and also with Electron Plus 3. This format is designated 'M'.
This format can be read from or written to on the Archimedes, but the Archimedes will not format M format discs. The
second is a 640k format compatible with the BBC Master and Compact, and the third is a new 800k format. Both of
these may be read from, written to and formatted. The 640k format is `L' format, the 800k is 'D'.
Software that is already on Master Compact format disks can be loaded into the Archimedes directly and then saved
again. If this software is written in BASIC it should run without modification, and other software, as long as it does not
access hardware directly, should run under the 6502 emulator.
The task of transferring software on 5 1/4 inch disc onto the Archimedes is a little more difficult. If the Archimedes is
on an Econet this job can be done by transferring the software on to the net using the *MOVE command on a Master
and then *COPYing the file back from the network on to the Archimedes. If no network is available, transfer can take
place using the respective serial ports. See the later section for details. If there is no serial port on the computer, then it
will be necessary to transfer the software via a computer that has a both a 5 1/4 inch drive and a 3 1/2 inch drive. A
Compact with a 5 1/4 inch drive as drive one is suitable for this excercise. If you are unfamiliar with the operation of
connecting a 5 1/4 inch drive to a Compact, please see the later section regarding this connection. Because of
certain restrictions with the Compact serial port, it is better to transfer software using discs.
Doc. 999,0031 December 1987 -2- Acorn Engineering News