New 'puter joins the collection

From: Pete Turnbull <>
Date: Mon Mar 12 13:16:55 2001

On Mar 12, 10:08, Mike wrote:
> From: Jim Battle <>

> > Do you know if you have the original, or the Sorcerer II?

> What's the difference between the two models?

Externally, practically nothing. Internally, the Sorcerer II has somewhat
different memory decoding, to accomodate 3 rows of 4116's instead of 2, and
they're all socketed. There's a DIP switch to select type and number of
banks, which was done by solder links on the original.

The video timing is also different, and it's easier to get a stable picture
at 50Hz on the Mk.II; one of the poles on the 4-way DIP switch controls
US/UK setting.

Some of the signals on the 50-way expansion interface are slightly
different. There's an MEMORY OFF input so an external device can switch
off the internal RAM. The RSET signal is derived slightly differently,

The Mk.II has fixed the hardware bug in the RS232 (on the Mk.1, the gate
signal to switch from cassette to RS232 was wrongly applied so the RS232
was forced to the wrong logic level when the cassette was selected).

Some of the layout is a little different to accomadate the changes, the IC
number has changed of course, and a few parts of the circuit are done with
(parts of) different ICs.

They're still the same clock speed (2.106 MHz), and (apart from the
differences above) the same machine.

Pete						Peter Turnbull
						Network Manager
						Dept. of Computer Science
						University of York
Received on Mon Mar 12 2001 - 13:16:55 GMT

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