i asked 'blitzchess', a french collector, some help to have more information about SC9 family.
i was very kind and sent me 4 and half SC9.
why 4 and half : because there are 4 full boards and a mother board without sensory surface, because of an upgrade.
with my 3 three SC9A that makes a good starting point to reorganize that mess in SC9 family.
he is a very lucky man :
all 4 four of his SC9 have different PCB.
and he got a ROM revision nobody else spoke about prior, to what i know:
in fact there are now (at least)3 revisions of the PCB of the SC9 and there are also 3 revisions of the software running in them.
there is a pcb : 510-1046 revision B01 which is running software :101-1034A01 and 101-1034A02
found in SC9 : 21482215
never heard before
there is a pcb : 510-1046 revision C01 which is running software :101-1034A01 and 101-1034B02
found in SC9 : 32170966
-> this one is what we commonly call SC9A
this board is running at various speed , at least at 1.5, 1.6 , 1.9 Mhz
date code we have (at least) for that revision : 8242/8243 and 8325/8326
there is a pcb : 510-1046 revision D01 which is running software :101-1034B01 and 101-1034C02
found in SC9 : 33296781
-> this one is what we commonly call SC9B
i haven't measured the real clock at the moment.
the hardware revision consist of suppressing a chip or replacing one by another one.
so we have now a small problem of labelling :
how to call each of the three revisions:
how, for example, name the revision B board that is prior to what we call SC9A. (revision C board).
and do we agree to call SC9B only those boards that have pcb : 510-1046 revision D01 which is running software :101-1034B01 and 101-1034C02
we know that there are at least two variants of that board : with ou without the daughter board.
Blitzchess is also a happy owner of the SC9 running at 8 mhz.
i have made some photos of that board. I know that some members are against upgraded board, even if myself i consider that rather positive if well realised.
on my flickr albums you will find all photos i took about all that mess of boards and ROMs, making albums for each revision of the boards.
https://www.flickr.com/photos/149310091@N02/albums
as it is for further investigations the photos are heavy (6 Mbytes each) in order to zoom without loss of quality.
i haven't tried to compress them a little.
i have still many things to do :
measure each clockrate
dump the ROM for the very first board ( i didn't manage to dump them for the moment)
some questions for larry and mike :
on the lower side of the revision D board there is a date code on the board i have: it is said 83 34 as week 34 of 1983.
so it suggest that that revision B was "technically introduced" at end of august 1983, even if commercially it is rather in october 1983.
that matches with the datecode on the ROMs : week 43/1983 at least for what we know for the moment.
may be they were just waiting the ROM to be produced.
do you have a datecode on your boards ?
as you see bliztchess board hasn't the daughter board, just the sandwich with two TTL chips one on the other.
we have opened the pandora box :
i think there are many other things that we can deduce from those photos and those boards, and further investigations.
we have now more data to rewrite the roadmap of SC9 model.
may be we could open a new topic like' SC9 different revisions'