Date   : Fri, 03 Jun 2011 02:01:21 +0930
From   : station240@... (Paul Asin)
Subject: Model B with video corruption

On 02/06/2011,@5:28 PM, Sprow <info@...> wrote:

> In article <COL120-W16F21639EC2809B38E7CD4837C0@...>,
>   paul aslin <station240@...> wrote:
> 
>> Also the machine completely hangs if NFS is swapped for DNFS, nothing 
>> wrong with the later rom as I downloaded it and used it in an emulator.
> 
> Check link S9, it may be sitting waiting for an 8271 NMI to clear.

Its an econet only machine, so S9 is hardwired. Same with the machine DNFS
came out of, better fix that before I put a 8271 in it.

My theory is there is a fault around IC 23, 24, 26, which is causing data
bus conflicts between chips. Either that or a faulty chip somewhere.