Musings of tinkering hands...

From: Bo Zimmerman (
Date: 1999-08-05 16:24:59

	The Commodore SuperPET SP9000 -- Wow, there are not one, but TWO revisions
of the SP9000 expansion board.  The older is a double expansion board,
feeding off the main power supply directly, having 16 or so memory chips to
make up the 64K expansion, and actually double-deckered over the main board.
The newer (the one I use) is a single integrated expansion board drawing
power from the little 5 pin port near the back of the main board, and having
only 8 memory chips.  This stuff is merely amusing, but not perplexing.

      What I don't understand though, is the last difference between them.
The older board had, mounted on the right hand side, a second pair of
switches in addition to the standard "Read/RW/Prog" and "6502/6509/Prog"
switches.  These other switches were two-position instead of three, and one
was marked "RAM/ROM" and the other was marked with the name of a chip
socket, and something like "disable, enable".  These switches were attached
in two places.  One was to a pair of chips in the expansion sockets of the
main board.  The other was to an extra 3 pin port on the lower of the two
expansion board (one not present on newer version).  Can someone with an
older  superPET tell me what this extra pair of switches does?  I couldn't
tell myself because there is apparantly something wrong with the memory on
the expansion board -- none of the languages would boot, but would lock up
the computer.

	BTW, why doesn't the standard 64K expansion software work with a SuperPET?
Is it addressed differently?

	The Commodore B500 -- Disappointing.  I imagined a 64K B128 with an older
BASIC in there.  Instead I got a B128 -- 128K -- BASIC 4.0.  The only
difference I can see is the eprommed kernal and BASIC chips instead of the
factory run chips.  Anyone have any different experiences with this machine?
At least it came with the box..

	- Bo

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