Date   : Tue, 31 Aug 1999 23:11:08 +0200
From   : "Mark Usher" <marku@...>
Subject: Re: and onto Beeb no 2 

> 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.


Mark