Date : Sun, 13 Apr 2008 22:17:40 +0100
From : C.J.Thornley@... (Chris Thornley)
Subject: Reviving a dead BBC+
Hi,
I suppose your next step is see if you can track down another donor BBC
until and swap socketed chips.
Your VIA's might be partly damaged have you tried swapping them around or
fitting fresh?
I found this reference to the 6512 CPU
http://www.izabella.freeuk.com/html/6502_cpu.html which explains some of the
physical differences i.e. 2 Phase Clock and DBE.
http://www.baltissen.org/newhtm/10to816.htm
You could cannibalise an old C64 for the 6512 chip or get a more recent and
readily available 65816 http://www.westerndesigncenter.com/wdc/ and build
this converter http://6502.org/mini-projects/816conv/conv.html or
http://www.baltissen.org/images/651016.gif
Chris
/> Christopher J. Thornley is cjt@...
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-----Original Message-----
From: bbc-micro-bounces+c.j.thornley=coolrose.fsnet.co.uk@...
[mailto:bbc-micro-bounces+c.j.thornley=coolrose.fsnet.co.uk@...
uk] On Behalf Of Mike Tomlinson
Sent: 13 April 2008 11:02
To: bbc-micro@...
Subject: Re: [BBC-Micro] Reviving a dead BBC+
In article <CA3F3CAD6A89405DAAE687FABE1A53B6@...>, Ken Lowe
<ken.lowe@...> writes
>Finally, I snipped the A9 & A10 lines to the memory RAS / CAS contoller
>IC51 but that made no difference (now I need to get a replacement
74LS257AN).
Piggybacking a new chip on top of a suspected faulty one is a useful
troubleshooting technique with dealing with 74LSxx logic.
>As far as I can tell now, the only component left is the 6512 CPU. I
>need to try and find a replacement from somewhere.
I'm pretty sure I have a spare 6512 somewhere. I used it in a BBC B so that
I could run the Master BASIC4 ROM. You're welcome to it if you cannot find
a replacement.
--
(\__/) Bunny says NO to Windows Vista!
(='.'=) http://www.cs.auckland.ac.nz/~pgut001/pubs/vista_cost.html
(")_(") http://www.cypherpunks.to/~peter/vista.pdf
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