Date   : Sun, 28 Sep 2003 12:39:58 +0100
From   : Sprow <info@...>
Subject: Re: BBC Micro lazy delayed boot!

In article <bq7VupBwKsd$EwsY@...>,
   Mike Tomlinson <mike@...> wrote:
> In article <6A4F555CEA3CD5118DBD0002E30AC0912C082B@...
> consultants.co.uk>, Andrew Hancock <Andrew.Hancock@...
> consultants.co.uk> writes

> >And I've just discovered this morning, the colder the machine the longer 
> >the
> >wait, because yesterday evening as the Beeb was left on the warmer it got
> >the quicker it booted.
>
> Check the power supply voltages with a meter.  This sounds like the
> classic C9 problem in the PSU.

But the fact that it makes some initial attempt to startup (albeit the first
and second beep are far apart) would imply there is juice coming out of the
PSU.

As I think another suggested prodding the nNMI and nIRQ lines on the CPU
with a logic probe would be a good first guess,particularly with the
relationship between removing and inserting the 8271.See if the slow startup
correlates with one of the two lines transitioning.

Also (my current favourite guess) would be to look at the output of IC16 and
IC33,giving the huge ceramic disc capacitor a wiggle,
Sprow.