Date   : Sat, 01 Nov 2008 21:54:22 +0000
From   : pete@... (Pete Turnbull)
Subject: Econet on BBC issue 3 , having problems

On 01/11/2008 20:47, Andy Ford wrote:

> I'm having trouble with an econet interface (not fitted by me) on an
>  Issue 3 'B'.

> Anyway, I made a link there (S5 south) and now I have got rid of the
>  No Clock message

That makes sense.  S5 is only used on machines that have the on-board 
clock; when made north, it enables it.  If you've not fitted the clock 
parts, or anytime  you are using an external clock, it should be made 
south, as you've done, otherwise the clock output driver jams the clock 
lines on the network.

> but I cannot get it to do anything. I have the 
> normal prompt but any attempt to access econet results in just a 
> hanging cursor, as if it is waiting for the server but it does not 
> time out with an error as I would of expected it to (although I only
>  left it about 30 seconds or so)

> Extra info: This issue 3 has a combined net and dfs rom (without 
> looking it's NFS 3.6 and DFS 1.2) , it is complete (minus the 8271) ,
>  I have not checked disk i/o although when it was last used a few 
> years ago when it had an 8271 the disk interface did function),

If the 8271 isn't fitted, has link S9 been re-made?  It controls the NMI 
from the disk controller.  The NMI is shared with the Econet, and if 
either isn't fitted but the appropriate link is still open, the NMI 
won't work properly.  And you've cut or removed S2, yes?  That's the NMI 
enable for the Econet.

> I have adjusted the clock speed with no benefit. I should add I have
>  the US clock (it is currently set at 230K, and this works fine with
>  the two M128's that are connected to my network)

Beebs won't go quite as fast as Masters, so it may be worth turning the
clock down one step.  It's not the main problem here, though.

> For "spares" , I have a dead issue 7 machine that has econet too, 
> although I do not know what components are still functional on this 
> (I was thinking substitution) , but issue 3 is laid out slightly 
> differently, and I think most of the econet may be damaged on the 7 ,
>  as most of this machine is a mess.

Most of the things that tend to fail are socketed ICs, so it may still
be useful.  All the parts of the upgrade are the same.

> as far as I can tell, none of the clock / terminator generation parts
>  are fitted to the 3 either.

They rarely are.  Acorn recommended against it, because if the machine
with the clock is turned off, so's your network; similarly if the
machines with the terminators are off, the terminators won't work
properly (they're active terminators in those machines, rather better
than the usual passive ones).

-- 
Pete                                           Peter Turnbull
                                               Network Manager
                                               University of York