Date   : Mon, 31 Oct 2005 19:27:43 GMT
From   : Pete Turnbull <pete@...>
Subject: Re: Guess age from serial number?

On Oct 31 2005, 14:02, Jules Richardson wrote:
> David Harper wrote:

> > Most later Model B's had the Issue 7 board. (It did seem a bit more
> > reliable than the earlier ones.)
> >
> > BTW, can anyone remember how many issues of motherboard there were?
I
> > can recall early beebs with Issues 1 to 4 and then Issue 7. I don't
> > recall Issues 5 & 6 ever being used (or were they for the
Electron??)
>
> I'm almost certain that 5 & 6 never happened; I think Pete Turnbull
> knows the story there (as has told it to me in the past, and I've
since
> forgotten, and I don't have any useful archives to hand ;)

Issue 1 was fairly short-lived, because there were several problems
with it, many fixed by Issue 2.  That still had some problems, with,
for example, the printer port, so Issue 3 came along quite quickly.
 Issue 4 deleted the Econet clock generator and terminator which had
been on previous boards, fixed the noisy sound and the printer
handshake.  I think 4 also added the link for colour on the compsite
video, or maybe that was 7.  5 and 6 were to improve the power and
ground connections but were never completed; after a certain point in
each case it was deemed better to start again.  I was told this had
something to do with Friday lunchtimes and visits to the pub but I
can't say for sure that's true :-)  Certainly Issue 7 was the next and
final release, and the major difference from Issue 4 is simply the
thickness and routing of power and ground tracks.


-- 
Pete                                           Peter Turnbull
                                               Network Manager
                                               University of York