Date   : Sun, 28 Sep 2003 19:45:35 +0100
From   : Sprow <info@...>
Subject: Re: BBC Micro lazy delayed boot!

In article
<6A4F555CEA3CD5118DBD0002E30AC0912C0838@...>,
   Andrew Hancock <Andrew.Hancock@...> wrote:

[snip]

> The problem still exist, I think I'll have to start checking logic states
> nNMI and nIRQ lines on the CPU with a logic probe and output of IC16 and
> IC33,giving the huge ceramic disc capacitor a wiggle as Sprow suggested.
>
> Which huge ceramic disc capacitor?

The one just next to IC16 (a 555).There are two actually,but only one
governs the reset pulse width.

> And how do I proceed with checking checking logic states nNMI and nIRQ 
> lines on the CPU with a logic probe and output of IC16 and IC33?
>
> Apart from first I'll have to purchase a logic probe!

Just an LED connected via a spare gate will do,or looking on a scope set to
1V/cm vertical.

I'm a little puzzled how DFS 0.90 and DFS 1.20 are different,particularly if
there's no NFS chip fitted,as NFS also has an intimate relationship with
nNMI,
Sprow.