Date   : Mon, 28 Apr 2008 08:30:33 +0100
From   : Steven.Bass@... (Steve Bass)
Subject: Reviving a dead BBC+

Hi Ken

Good piccies, most impressive.

I noticed the DFS version 2.22, not come accross this version before.

Any chance of a copy please?


Regards


Steve

----- Original Message ----- 
From: "Ken Lowe" <ken.lowe@...>
To: <bbc-micro@...>
Sent: Saturday, April 26, 2008 11:35 AM
Subject: Re: [BBC-Micro] Reviving a dead BBC+


> Ken Lowe wrote:
>
>>>>I intend to get hold of another 32K RAM chip and build a small circuit
>>>>board that will hold both 32K RAM chips, and a single 32K ROM.
>>>>This circuit board will then plug into one of the existing ROM sockets,
>>>>with flying leads to the three external points highlighted above, and a
>>>>fourth to pick up page 0/1 select. This should provide me with a fully
>>>>expanded 128K B+ with all ROM sockets still available.
>
>>> Very nice :)  I'd like to see photos of that if possible.
>
>> I'll post up some pics once I receive all the bits (waiting on 28 pin
>> sockets and RAM chips). Initially I'll build it on breadboard, so it 
>> might
>> look a bit messy. If it works as I expect, then I might make a proper PCB
>> to
>> make it look a bit neater.
>
> Ok. It's all up and running. Photos are here:
>
> http://i300.photobucket.com/albums/nn18/chaser2001a/BBCPLUS128K/PICT1020.jpg
> http://i300.photobucket.com/albums/nn18/chaser2001a/BBCPLUS128K/PICT1019.jpg
> http://i300.photobucket.com/albums/nn18/chaser2001a/BBCPLUS128K/PICT1030.jpg
> http://i300.photobucket.com/albums/nn18/chaser2001a/BBCPLUS128K/PICT1052.jpg
> http://i300.photobucket.com/albums/nn18/chaser2001a/BBCPLUS128K/PICT1053.jpg
> http://i300.photobucket.com/albums/nn18/chaser2001a/BBCPLUS128K/IMG_1351.jpg
>
> The left most socket on my board is a direct replacement for the host 
> socket
> (IC62) on the mainboard. The other two sockets contain the 32K RAM chips,
> both of which can be write enabled / disabled using the connected 
> switches.
> My board doesn't actually need to be plugged into the IC62 socket - it can
> be plugged into any of mainboard ROM sockets (apart from the BASIC / OS 
> ROM
> socket, obviously). I may need to move my board if / when I get a GoMMC 
> for
> the B+.
>
>> I've also ordered some bits to build an eprom programmer so I can create 
>> a
>> 32K ROM with both ADFS (for my HDD), and DFS. I don't have the standard 
>> B+
>> DFS1770 V2.22 on EPROM and currently I'm having to copy it from my HDD
>> into
>> the upper half of my new 32K RAM bank in order to see the ACORN OS 96K
>> message.
>
> Built the EPROM programmer too using this
> http://www.bbcmicro.net/old-8bs/submit/subeprog.htm. I didn't bother with
> the voltage regulator part of the circuit - instead I used a spare 12V
> supply that I had lying around. Decided not to take photos of it. It's 
> built
> on breadboard, and looks a little messy! I had to modify it slightly to
> program 32K EPROMs (basically I programmed 2 x 16K banks). You'll see that
> I've created a ROM with ADFS1.30 & DFS2.22. I made ADFS the higher 
> priority
> ROM because I prefer to boot to my HDD. DFS 2.22 gives me the SRAM 
> utilities
> and allows the boot up screen to show the amount of sideways RAM installed
> (now saying ACORN OS 128K when both write protect switches are in the 
> write
> enable position).
>
> Ken.
>
>
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