Date   : Wed, 01 Oct 2003 04:54:46 +0100
From   : Mike Tomlinson <mike@...>
Subject: Re: 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.

>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?

>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?

>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?

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