Date   : Sun, 25 Apr 2010 21:16:59 +0100
From   : mike@... (Mike Tomlinson)
Subject: BBC B with odd screen fault

In article <273353483A4A4391AA812BB8CBB5F35D@...>, Mark Haysman
<jumbos.bazzar@...> writes

>    If it's happening in all modes, and the Beeb still seems to run 
>    things okay, then it's unlikely to be RAM, as that would also crash 
>    the machine. You could try a different Video ULA, as it's socketed, 
>    apart from that, if you have changed the LS245, then it's probably 
>    something deeper in the video circuitry.

It sounds like an addressing fault.  I'd swap the LS245 first then try
piggy-backing the 81LS95s.  Could also feel the chips with the back of a
finger to see if any seem unusually hot or cold.

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