Date   : Wed, 01 Sep 1999 11:38:46 +1200 (NZST)
From   : Bill Keesing <bill@...>
Subject: Re: and onto Beeb no 2 

On Tue, 31 Aug 1999, Mark Usher wrote:

> 
> > I'd check the 68B54; swap it for another if it's socketed.  Check that S2
> > (next to the ADLC) is right - I think it should be open when Econet is
> > fitted.  See what the 68B54's interrupt line is doing, in
> > particular whether it seems to be stuck on (low).
> 
> Right, I have 3 68b54's. All three work fully in the Beeb #1 repaired
> yesterday. When inserted in Beeb #2 that is causing the problem, only one of
> them detects the DNFS chip and boots into NET mode.
> This is with the NMI (S2) disabled. When it is enabled, with all 3 chips the
> beeb hangs. When the beeb hangs the 68b54 interrupt line is stuck low.
> 
> I changed all the econet related chips for a good set without any change.
> This is now somwhat of a puzzler.

Just a shot in the dark, but are the ROMs in the right order? IIRC some
of the ROMs needed to be in higher priority sockets than others. And IIRC
the highest number socket was the first in terms of proirity when poled
at boot.

 -- 
Bill Keesing
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http://www.keesing-keay.gen.nz/~bill/index.html

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