Date : Tue, 19 Apr 2011 11:34:17 +1000
From : awilliams@... (Alan Williams)
Subject: Anyone have an Acorn "System" memory card?
-----Original Message-----
From: Jules Richardson [mailto:jules.richardson99@...]
Sent: Tuesday, 19 April 2011 9:09 AM
To: Alan Williams
Cc: peteveg@...
Subject: Re: [BBC-Micro] Anyone have an Acorn "System" memory card?
Pete G. wrote:
> Pete, don't give up yet I haven't looked in my shed.
Hey guys,
[I didn't see Alan's post via the list... I think gmail must have eaten
it
:-) ]
Pete, I'll probably have a spare board *eventually* if needed, too. I'm
pretty sure I had a spare Acorn 32K board (I can't remember if it was
populated, but I'm almost certain I have a stash of the right RAM chips,
too). Sadly it's all locked away in storage overseas and I don't have an
ETA for getting it here with me, but keep it in mind, anyway.
I also have quite a stack of CU boards, so one of those would probably
work (but your comment about wanting to keep it 'all Acorn' noted :-)
> My System4 presently doesn't work and I haven't resolved why, I
> suspected the memory boards of which there were two.
My System 3 was a mess - many of the ICs had visibly rotted pins, but
quite a few of them looked OK but broke when you so much as sneezed near
them; I think I ended up replacing over 50% of the ICs in the thing
before it ran.
> I was trying to
> replace these with a single one from Control Universal, using just 8K
> CMOS RAM chips for the whole memory map on the one board, but so far
> that this hasn't worked either.
Yes, I'm not 100% certain that those boards will work - it's on the
to-do list (when I have them here) to reverse-engineer them and work out
what the switches / jumpers / PALs do.
I'm pretty confident that their DRAM boards are basically a drop-in
replacement, but the ones marked 'cumem' and 'cumem-selecta' are a bit
of an unknown.
> It might also be bit rot in the ROMS and I don't have images of
these.
I think we went through this conversation off-list a few years ago, but
I can't recall the result :-) (my brain has more bit-rot than most
vintage Acorn machines). I have a System 5 8KB image here which you
could try, plus a couple of System 3 ones (and I believe - without
digging through emails to check - that the S3 one with Econet came from
you in the first place)
> I also have a shoe box with a number of other cards I will look what
> there is and let you know.
I'd be interested in the findings there - I recall you mentioning the
Acorn shoebox before :-) Can I possibly trouble you for some board
photos if there's anything unusual? Looking at my boards, I don't have
images for the
following:
200,003 8KB RAM/ROM
200,006 Block-relocating ICE
200,007 PROM programmer
200,014 Analogue interface
200,017 Interface panel
200,018 Daisywheel printer interface
200,021 IEEE-488 interface
200,027 8KB CMOS RAM
200,031 Bus interface
> Adding a memory board to a working system would make it much easier to
> identify a faulty RAM chip than having a system that won't boot at all
> in the fist place. If I still had spare memory chips 2114 or what
> ever I would give you some of them too.
Yes, couple of 2114's on a 6502 board, 6116 on the 6502A, and 4816's
(and friends - IIRC there was a whole bunch of compatible DRAM ICs with
the same
pinout) on the Acorn 32K board.
cheers
Jules
I have taken photos of the 200,003 8K rom/ram that's the only one you
list that I have. I only ever saw these units as fileservers in
Australia, thus I have never seen any of the more interesting boards.
The loose Acorn boards I have include
6502
6502A
8k ram/rom
32k dram
40x25 vdu
Econet (without on board clock)
My System box currently has in it
6502
40x25 vdu
Econet (without on board clock)
8271 FDC
[No memory boards at present]
I have Cumem which I mentioned before.
I also have the CU BEEB-EX 1MHZe bus adaptor with four slot backplane.
The pix for 200,003 are now here
http://earlthecamel.com/200,003/
sorry they are a bit huge.
Alan