Date   : Mon, 13 Nov 2006 20:59:05 +0100
From   : danielg@... (D.G. van der Pol)
Subject: 128K Upgrade Board - Fitting Howto

Op 12-nov-2006, om 10:39 heeft Mike Howard het volgende geschreven:

> D.G. van der Pol wrote:
>> This sounds like a Solidisk 2/4Meg upgrade. As you might have
>> guessed, this one has 128k ram, used for sideways- and shadow ram.
>> I think the instruction manual should be on BBC Lives! <http://
>> www.nvg.ntnu.no/bbc/doc/Solidisk-2and4meg-manual.rtf>
>>
>> I have a 4meg/256k board from Solidisk. The ram part of the board is
>> OK, but the 4MHz is very unreliable.
>>
>> I used this board primairy for Interword, as you have a lot of
>> sidewaysramsockets & shadow ram.
>>
>> Have fun!
>>
>> Daniel G.
>>
>>
>> Op 11-nov-2006, om 9:36 heeft Mike Howard het volgende geschreven:
>>
>>> Hello All,
>>>
>>> I have a 128k upgrade board for a BBC/B but unfortunately I don't  
>>> have
>>> the fitting instructions.
>>>
>>> The board is marked '6502' above the 6502 chip and 'TWO' 'MEG' '128'
>>> (printed underneath each other)to the left of the 6502 chip.
>>>
>>> It has a switch wired from the top edge of the board and 3 wires
>>> soldered to the bottom edge (underside) of the board.
>>>
>>> Obviously, it plugs into the 6502 socket on the motherboard but  
>>> which
>>> header (S20? S22?) and in which order do the 3 wires attach? The  
>>> wires
>>> are coloured black, brown and red.
>>>
>>> Anybody any idea?
>>>
>>> Any help appreciated.
>
> Hi Daniel,
>
> Thanks for the info and the link. It certainly sounds like the  
> Solidisk
> board but ithe installation instructions pointed to by the link you
> provided refer to; "two spring clips to be clipped on to points in the
> BBC micro."
>
> The board I have here only has the three wires, no sign of spring  
> clips.
> I suppose I could try connecting those as per the instructions and see
> what happens, or maybe doesn't happen :)
>
> Cheers,
> Mike.
> -- 
> Mike Howard                       aixguru at blueyonder dot co dot uk
> Eccleston                 (Hotmail Reply-To is a spam trap)
> UK
>
>
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>

My excuses for topposting in my first reaction.

As I told you, I have the 4Meg version, this one needs a 4Mhz clock  
from some point. Maybe the 2Meg doesn't need those. I just had a look  
at my Solidisk 4Meg again. It contains a GTE 65SC02-4, four 28 pin  
romsockets, eight 256kbit dram chips, one 64kbit 6264 sram chip and a  
lot of 74LSxx chips.

The board is in place of the 6502 processor and is connected by 5  
wires to  the motherboard. Three of them are going to S20 , S21& S22.  
They are on the edge of the board, near the keyboard. On my board  
they are marked, from left to right: S21, S22 & S20, the wires are  
coloured blue, purple & gray.

Then two wires come from two corners, the one near the back of the  
computer is marked 4Mhz clock and connected to pin12 of IC43.
The other one, near the keyboard is marked ROM SELECT and connected  
to pin 9 of IC76. These last two used to be connected via spring  
clips, but that was extremely unreliable, so I soldered them straight  
to the motherboard.

Finaly the board has a switch, connected to two points in the middle  
of the board, which let you switch between 2 and 4Mhz.

My board does not have any marking stating the name Solidisk, so that  
might be a clue.

Oh, the board came with a "256 manager 3.01" rom, which contains the  
software described in the manual.

If you want me to, I can make some photographs of it, to send to you.  
Let me know.