And now, for some pics!
Here is my LC630 DOS board stripped of all its extra goodies, basically a standard two-slot 630/580 series board, which has neither a ROM SIMM slot, nor solder pads for one:
And here's my LC630's original board, which is the earlier revision board and does have the solder pads for the ROM SIMM slot:
I'd say that they put the ROM SIMM slot in the first revision board, so that it was there in the event it was needed, but found it unnecessary in the next revision. These are the only two revisions of the 630/580 series board that I'm aware of - if yours is different, please, post pics!
Here is my LC630 DOS board stripped of all its extra goodies, basically a standard two-slot 630/580 series board, which has neither a ROM SIMM slot, nor solder pads for one:
And here's my LC630's original board, which is the earlier revision board and does have the solder pads for the ROM SIMM slot:
I'd say that they put the ROM SIMM slot in the first revision board, so that it was there in the event it was needed, but found it unnecessary in the next revision. These are the only two revisions of the 630/580 series board that I'm aware of - if yours is different, please, post pics!