Date   : Sun, 28 Sep 2003 17:44:45 +0100
From   : Andrew Hancock <Andrew.Hancock@...>
Subject: Re: BBC Micro lazy delayed boot!

 
 
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Jules

Thanks for this.

I've just checked all connections on the underneath of the PCB, and
re-soldered all 40 pins of the 8271 socket, I'll order a new DIL socket and
replace it.

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?

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!


Regards

Andrew

-----Original Message-----
From: Jules Richardson [mailto:julesrichardsonuk@...] 
Sent: 27 September 2003 23:25
To: Andrew Hancock; 'bbc-micro@...'
Subject: Re: [BBC-Micro] BBC Micro lazy delayed boot!

Hiya,

> When the 8271 chip is inserted, if I power-on the Beeb, I get the first
> tone, flashing cursor and 4 seconds later the second tone and the Beeb
> boots, and displays usual BBC Computer 32K, Acorn DFS, Basic.
> 
> This also occurs when I Press Break, four second delay (but no sounds -
> normal), and CTRL-BREAK, four second delay (usual beep).
> 
> The Beeb boots/powers-on correctly when No 8271 chip is inserted. But no
> Acorn DFS is loaded/present.

Random thought (and someone else might have already suggested this; I'm
being
flooded with virus emails at the moment and missing out on half of my proper
emails)...

It's not something silly like a bad solder joint or even a washer or
something
else conductive trapped under the circuit board is it - and you've just been
unlucky that the problem's shown up every time you've stuck the 8271 chip
in?
You may already have the board out on the bench of course which would rule
out
the latter possibility.

cheers

Jules

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