Date : Wed, 05 Sep 2007 13:52:02 +0100
From : bbcmailinglist@... (Ian Wolstenholme)
Subject: Econet oddities and ATPL boards! - Resolved!!
Thanks for letting me know about this, I will certainly look into it and
update the Econet fitting instructions accordingly.
That is, if I can get any more parts for some more kits!!
Best wishes,
Ian
----- Original Message -----
From: Chris Priest [mailto:chris.priest@...]
To: bbc-micro@...
Sent: Wed, 05 Sep 2007 09:01:40 +0100
Subject: [BBC-Micro] Econet oddities and ATPL boards! - Resolved!!
Hi All,
Thought you might be interested in this, I managed to solve my problems
with my ATPL board and also the econet issues I was having.
I'll start with the ATPL issues.
Turns out the board had been modified, for what purpose I am not sure,
it had a custom MOS chip in a 27128k chip, pins 1 and 28 had been linked
by a short piece of wire and the original track to pin 28 cut.
Repairing this and replacing the MOS rom with a standard Acorn one,
fixed the problems with the ATPL board.
But, I had a new problem! After a while the beeb would slow down until
it was unusuable, this occoured even without the ATPL board fitted and I
couldn't think why.
So, got to thinking.....
This was the machine that I had just fitted one of Ian's excellent
Econet upgrades to, before you say anything Ian, the kit is fine :)
What actually happened was this.
I read your instructions to the letter, including disregarding the
requirement for IC86 I think it was 74LS123 if you had a disc interface
fitted. Now I had a disc interface fitted, but it's a 1770 interface,
one I fitted as an upgrade to what was a cassette based only system,
IC86? only had a wirelink between pins 8 and 11 I think it was, this was
a requirement of the 1770 upgrade if this chip was not fitted.
So, I took it for gospel and didn't do anything, unfortunately with this
chip missing, it caused all of my problems with the econet, including
random no clock messages, or not working with the terminators fitted
etc, it also appeared to cause this slowdown issue I was experiencing,
fitting an 74LS123 kicked the econet into life and touch wood, no
problems with speed either!
So, Ian, a suggestion, it might be better to say the chip is needed *IF*
you only have the wire link fitted due to a 1770 upgrade, I appreciate
the chip exists with a standard 8271 interface.
Anyway, happy bunny, Beeb working on econet and running the ATPL board
quite happily :)
Anyone care to point out why this modification was required to run a
custom MOS? I am not sure on that part.
Best Regards
Chris
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