Date   : Sat, 02 Sep 2000 22:33:32 +0200
From   : "Mark Usher" <mu.list@...>
Subject: Re: model B saga continues

> >If you have removed the DFS (not just the DFS ROM but all the DFS upgrade
> >chips) then you should also close jumper 9.
> Thanks!
> Where is jumper 9??
Jumper 9 is near the 8271 chip

> >You can check the upper and lower banks of RAM by using jumper 25.
> >removed selects CAS 0 (16k)
> >south selects CAS1 (16k)
> >North selects both (32k)
>
> Thanks Mark!!
> What does the above mean????
> where do I find jumper 25, and what do I do with it?
Oh dear. CAS 0 is the lower 16k of RAM and CAS1 is the upper 16k of RAM (or
is that the other way round).. If there is a faulty chip in one of the RAM
banks this is one way to try and find out. Just swap the jumper round as
detailed above. Jumper 25 can be found between the left most ROM socket and
the VIA.

Most of the information you need is in the BBC Service manual which can be
downloaded from the doc project web site.

> This is getting very interesting!!!
If you don't understand what all this means I really don't think you should
be playing around with the insides of a computer, with the vision of seeing
it working again.


Mark
BBC Documentation Project
http://members.magnet.at/marku/bbc/