On 27/02/2011 20:55, Ralf Reköndt wrote:
Phill Harvey-Smith wrote:
Hi all,
I have here a Sandy SuperDisk interface which works fine. The board
however has several (3) missing chips and a missing 9 pin socket, I know
from the manual, that this can be upgraded to a SuperQBoard, by fitting
the missing chips and the 9 pin mouse socket.
What I don't know is what the missing chips should be ? So does anyone
have a schematic, or failing that a good picture of the circuit board so
that I can see what the missing components are.
I once had a full blown SuperMouseBoard from Sandy (it was "updated" [in
fact, changed, not modified] from an SQB). I fear, one of the missing
chips is a programmed GAL chip. Seems to be very difficult to update the
board by yourself.
Humm The SuperDisk does have a 16l8 PAL on it, I've dumped and
disassembled this and it does have inputs that come from the missing
chips. Also the only empty 20 pin socket seems to have pins 1 and 19
connected together, which smacks to me of a 74ls24x where x=0,1,2,4,
possibly a buffer for the mouse inputs ?
And you have to have the right EPROM, as there is code for the "mouse"
logic.
Indeed which is why I was asking for a dump of it too......
Cheers.
Phill.
--
Phill Harvey-Smith, Programmer, Hardware hacker, and general eccentric !
"You can twist perceptions, but reality won't budge" -- Rush.
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