Date   : Mon, 03 Dec 2001 20:59:27 GMT
From   : pete@... (Pete Turnbull)
Subject: Re: Help!!

On Dec 3, 11:21, George Reynolds wrote:

> >You probably also need to replace the links on S21; there should be two
> >links running east/west.
>
> Sorry. Could you elaborate on this please. I am unsure what you mean!

OK.  If it's a BBC B (not a B+ or Master 128) there are several sets of
selection links in the form of Molex jumpers on square pins.  Slightly to
the left (west) of centre of the board, there's a group which includes 4
pins together, labelled S21.  These control the way the ROM select signals
are sent to the five on-board ROM sockets.  The normal setting is to have
two links on these pins, running east/west.

With some sideways ROM/RAM boards, those links -- or at least one of them
-- would be removed to allow the sideways board to control the ROM selects.
 Not all boards do it this way, and I can't remember if the Watford ones
did (they made more than one type).  If the links aren't BOTH there, you
need to replace them.

> Does anybody know how much these BEEBs are valued at?

Not very much.  They're fairly common.  To give you an idea, when I wanted
some spares recently, I was offered Beebs by two or three people, all for
less than a tenner, and one for free.

> Does the watford have connections to another socket towards the back of
the circuit board? I could get it to fit into the socket in front of the
keyboard, but it didn't seem to line up :s?

Not sure about the Watford boards, some versions probably did.  The socket
at the back is the one for the 7002 analogue-to-digital converter, and the
ATPL "Sidewise" board was the first design to have pins to fit that; it was
a convenient way to get access to the data bus and possibly other signals.
 The early Watford boards only connect to the ROM socket(s), and they don't
work very well because they're not fully buffered (so don't work well with
a full complement of EPROMs) and tend to tip over, causing erratic
connections, because they're only supported in one corner.  I've still got
one of those (not in a machine!) and I've only seen one worse board (which
I've also got -- I wrote some reviews when those things were current).

> If anybody has any beeb ROMs or other hardware which they would like to
donate to me, please let me know!!

There are various web sites with images you could download and blow into
EPROMs.

-- 
Pete                                           Peter Turnbull
                                               Network Manager
                                               University of York