To:   Paul, Dick, Steven, Raymond, Fai, Ken
CC:   Howard
From: Jonathan
Date: 10 Dec 1992

RE:   Upgrading BBCs and TU1/3 teletext units.



Master Compact
==============

The compact has five EPROM sockets vertically down the lefthand side:

+----------------------------------------------------------------------+
|                               back                                   |
|                                                                      |
|                                                                      |
|                                                                      |
|                                                    +------------+    |
|                                                    |  CC2 V4.0  |    |
|                                                    +------------+    |
|                                                    +------------+    |
|                                                    |  CC1 V4.0  |    |
|                                                    +------------+    |
|                                                    +------------+    |
|                                                    |  (empty)   |    |
|                                                    +------------+    |
|                                                    +------------+    |
|                                                    |  AMS V5.5  |    |
|                                                    +------------+    |
|                                                    +------------+    |
|                                                    |   (MOS)    |    |
|                                                    +------------+    |
|                                                                      |
|                              front                                   |
+----------------------------------------------------------------------+

The Compact will not work with the double rom CC1&2.  It uses the three rom
set.  You won't usually need to change the configuration settings, but if
you do, they are as follows:  Hold down thr 'R' key and turn on the machine.
Message 'CMOS ram reset' appears.  Press Break again.  Type the following:

*INSERT 1
*UNPLUG 13
*CONFIGURE LANG 1

Press CTRL-Break, and the terminal will be entered.

























BBC B (German/US model)
=======================

This BBC usually has a lot of metal shielding and has five rom sockets
horizontally at the right edge, near the middle.  The roms are usually
underneath the teletext hardware:

+----------------------------------------------------------------------+
|                              back                                    |
|                                                 link15               |
|                                                   oo                 |
|                                                   oo                 |
|                                          +---++---++---++---++---+   |
|                                          |   ||   ||   ||   ||   |   |
|                                          | M ||   ||   ||AMS||   |   |
|                                          | O ||   ||   ||   ||   |   |
|                                          | S ||   ||   ||5.5||   |   |
|                                          |   ||   ||   ||   ||   |   |
|                                          +---++---++---++---++---+   |
|                                           IC71 IC72 IC73 IC74 IC75   |
|                                                                      |
|                                                                      |
|                                                                      |
|                              front                                   |
+----------------------------------------------------------------------+

This BBC can take either the CC1&2 double rom or the CC1 and CC2 single
roms.

           IC71: MOS                       IC71: MOS
           IC72: CC1&2 V4.0                IC72: CC1 V4.0
           IC73: empty                     IC73: CC2 V4.0
           IC74: AMS 5.5                   IC74: AMS V5.5
           IC75: empty                     IC75: empty
           S15:  east (right)              S15:  west (left)

The other links S14, S16 and S17 must be west (left)
            and S12 must be east (right).


BBC B (UK model)
================

This doesn't have any metal shielding and the rom sockets are near the front
right, underneath the keyboard.  The UK model cannot take the CC1&2 rom, and
must use the CC1 and CC2 roms.

+-------------------------------------------------------------------------+
|                              back                                       |
|                                                                         |
|                                                                         |
|                                                                         |
|                                                                         |
|                                                                         |
|                                                                         |
|                                                                         |
|                                                                         |
|                                                                         |
|                                                                         |
|                                                                         |
|                                              +---++---++---++---++---+  |
|                                              |   ||   ||   ||   ||   |  |
|                                              | M ||   ||AMS||CC1||CC2|  |
|                                              | O ||   ||   ||   ||   |  |
|                                              | S ||   ||5.5||4.0||4.0|  |
|                                              |   ||   ||   ||   ||   |  |
|                                              +---++---++---++---++---+  |
|                              front                                      |
+-------------------------------------------------------------------------+



Teletext Display Unit
=====================

This just has one rom, in socket IC1, and takes a TU1/3 V3.0 rom.  The
monitor output and teletext input sockets are identical and un-marked.
Looking from the back, from left to right the sockets are:
    Mains input,  Teletext input,  Monitor output,  Keyboard input