Date   : Wed, 01 Oct 2003 09:59:07 +0100 
From   : Andrew Hancock <Andrew.Hancock@...>
Subject: Re: BBC Micro lazy delayed boot!

> -----Original Message-----
> From: Mike Tomlinson [mailto:mike@...]
> Sent: 01 October 2003 04:55
> To: bbc-micro@...
> Subject: Re: [BBC-Micro] BBC Micro lazy delayed boot!
> 
> In article <6A4F555CEA3CD5118DBD0002E30AC0912C0852@...
> consultants.co.uk>, Andrew Hancock <Andrew.Hancock@...
> consultants.co.uk> writes
> 
> >With 8271 chip installed.
> >
> >So far, many contributors have stated check
> >
> >1. Outputs of IC 16
> >
> >IC 16 555 Output
> >
> >Pin 3 (input to IC 33) RST Transitions from high to low very quickly.
> >Stays LOW
> >
> >IC 33 74LS04
> >
> >Pin 3 Transitions from high to low very quickly.
> >Pin 4 (output) (bar) RST Transitions from low to high very quickly. Stays
> >HIGH.
> 
> All normal.

okay

> 
> >IC 1 6502
> >
> >Pin 4 High to Low at power-on, then High with pulses of low > 30ns
> 
> Normal.
> 
> >Pin 6 NMI PERMANENTLY HIGH. No transition observed.
> 
> Hmm.  Would have expected to see some transitions to low.  Does it go
> low if you do a *CAT from the command line?

When doing an *CAT, no transitions are observed. I must point out that no
floppy disc drive is connected. 

Does this make a difference?

> 
> >WITHOUT 8271 installed.
> >
> >As above.
> >
> >Except IC 1 6502
> >
> >Pin 6 NMI PERMANENTLY LOW No transition observed.
> 
> No, this is wrong.  It should be pulled high by R81.  Check this for dry
> joints.  If ic27 is socketed, does it go high if ic27 is taken out?
> What is the status of link S2?

No dry joints. I've resoldered all the pads around this area.  Bottom of R81
High (connected to +5v), top of R81 low (connected to pin 6 6502).

Link S2 is present.

IC27 is not socketed, shall I remove it? And re-test without IC27?

> 
> >I'm not too sure if I've mentioned this previously but with the 8271 chip
> >installed, the 15 second delay only occurs, when the DNFS 1.2 rom is
> >installed.
> 
> Okay, so if DFS 0.9 is installed, does the disc interface actually work?
> 

If DFS 0.9 and 8271 are installed, the machine still delays for 15 seconds
at power-on, but rather than displaying a flashing cursor, it displays the
full 

BBC Computer 32k
Acorn DFS
_ flashing cursor here, long beep for 15 seconds then
BASIC
>

DFS 0.9 installed and without the 8271 installed, at power-on

BBC Computer 32k
Acorn DFS
_ flashing cursor here, long beep BBC never gets to Basic. 

I've not connected a floppy disc drive to the Beeb as yet, because of this
problem and I didn't want to complicate matters with a floppy drive
connected. The Beeb should power-up quickly without a floppy drive
connected, and without the 8271 installed, DFS 0.9 shouldn't think a disc
controller chip is fitted. 

Regards

Andrew

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