Date   : Thu, 21 Sep 2000 08:15:29 +0100
From   : Mike Tomlinson <mike@...>
Subject: Re: 2nd Processors (Again)

In article <OE55eWgUSp3sJWGYdRG000007b5@...>, Julian Stenning
<julian_stenning@...> writes

>Hi Mike,
>
>thanks for the reply.  The diags on both beebs I have report the 2nd
>processor as not present :(

It is most likely faulty then, because I know that test works.

>The other bbc is a plain issue 7 board with 8271 controller. The only rom is
>acorn dnfs 1.2. It's becuase this machine is so 'plain' I suspect the 2nd
>processor.

good thinking. DNFS also has the Tube host code in it.

>One other question - *help returns 6502 TUBE 1.10 - is this the usual
>version? It's just the rom on the 2nd processor board has '6502 boot rom iss
>1.1' written on it in biro.

yes, that's ok.

>Any other ideas?

Have you tried the usual suspects, like HIBASIC? Do they run OK?  You do
get 'Acorn TUBE 6502 64k" on control-break?

You could whip off the lid and check that its PSU is working and feeding
5v to the main board.  The only way forward I can think from there would
be to get out a 'scope and logic probe, and make sure the 2nd processor
is actually running.  As I said earlier, the 9C ULA chip is the most
likely suspect - you will see it is socketed.

Mike

-- 
Mike Tomlinson
mike@...