Date   : Sun, 28 Sep 2003 15:06:08 +0100
From   : "Chris Thornley" <C.J.Thornley@...>
Subject: Re: BBC Micro lazy delayed boot!

Hi,
Isn't there an order you have to have roms in i.e pripority in there
sockets so they are initalized in a certain order?

I seem to rember but have to check that on certain motherboard revisions
jumpers had to be cut.

Chris


               />      Christopher J. Thornley is
cjt@...
  (           //------------------------------------------------------,
 (*)OXOXOXOXO(*>=*=O=S=U=0=3=6=*=---------                             >
  (           \\------------------------------------------------------'
               \>       Home Page :-http://www.coolrose.fsnet.co.uk
 

-----Original Message-----
From: Majordomo List Manager [mailto:majordomo@...] On Behalf
Of Sprow
Sent: 28 September 2003 12:40
To: bbc-micro@...
Subject: Re: [BBC-Micro] 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.