Date   : Mon, 20 Jun 2005 19:45:46 +0100
From   : "BeebMaster" <beebmaster@...>
Subject: Re: A couple of questions - Econet & 1770 Disc Interface

Are you sure they are Issue 4 Beebs?  Earlier issues of the motherboard had
circuitry for clock and
terminator before external clock boxes were invented so it is just possible
they are early Beebs
with the clock components added although I would think this is very unlikely
as I have never seen
one.

The only other explanation is either a faulty Econet interface or a faulty
disc interface or
something else interfering with the Econet signals.  I think if you attach
a sideways RAM module to
the BBC and connect the flying lead to the wrong leg of one of the chips
which give it the
write-enable signal then you end up with a clock signal appearing, so that
could be the
explanation.

First of all I would try issuing a *. or *I AM etc and see what error message
you get.

Best wishes,


Ian

----- Original Message -----
From: Mike Howard
To:   bbc-micro@...
Sent: Mon, 20 Jun 2005 15:58:33 +0100
Subject: [BBC-Micro] A couple of questions - Econet & 1770 Disc Interface

Hi All,

I have a few BBCs which, for reasons I won't bother you with, I'm about 
to ECONET together. With Econet fitted to an Issue 7 BBC/B I get the 
expected boot up message 'Econet Station xx No Clock'. With Econet 
fitted to a couple of Issue 4s I get no such message even though they 
are not yet networked and therefore there is no clock. Is that normal? 
I'll no doubt find out when I do actually wire up the network but I just 
thought I'd ask before I go any further.

I also have an Issue 7 BBC/B who's history I know little about (I 
believe it came from the Depatment Of Chemical Engineering at Nottingham 
University) and cannot get the disc interface to work. I'm using a known 
good floppy drive, known good disc interface, known good 7438s and the 
link is fitted at IC86. IC87 is fitted with a 74LS123 but unfortunately 
not socketed.

If I do a *cat, the drive led lights up, the disc whirrs then nothing, 
the led goes out and the beeb just sits there until I press ESCAPE. If I 
do a *form 80 0 the led lights up, the disc whirrs, the initial 
'formatting track 00' message appears and then the beeb hangs again. 
This time requiring a CTRL BREAK.

Is there anything simple/obvious that might make this happen or does it 
sound terminal (as far as disk is concerned)?

Any help appreciated.

Cheers,
-- 
Mike Howard                    aixguru at blueyonder dot co dot uk
Eccleston                       (Hotmail Reply-To is a spam trap)
UK