Re: How to tell diff between ROM 00 and 01 GS board?

[dempson@actrix.gen.nz (David Empson)]

RedskullDC <RDC@oz.org> wrote:

> "Dan Foster" <usenet@evilphb.org> wrote in message
> slrncff392.ig3.usenet@gaia.roc2.gblx.net">news:slrncff392.ig3.usenet@gaia.roc2.gblx.net...
> > If all I have are photographs, how do I tell the difference between a
> > ROM 00 and ROM 01 GS?
> 
> You could look for the presence of the keyboard socket which accepts
> the apple 2e keyboard.
> *Most* ROM01 machines, but not all, just have the solder pads, while
> the ROM00 machines have the socket installed, at least all the ones I
> have ever seen.

That is far from conclusive, because a ROM 00 machine might have been
upgraded to ROM 01.

There are only two operationally significant differences: the ROM chip
itself (342-0077A vs 342-0077B), and potentially the VGC (Video Graphics
Controller): the original one (revision -1 or -A according to my earlier
notes) had a design flaw which caused display problems in DHR mode, and
in some cases also in 80-column text mode.  Both chips can be upgraded
independently, but the free upgrade from Apple replaced both.  Later ROM
00 machines may have been supplied with the updated VGC.

You might not be able to spot the VGC from a photo, because it is
underneath the power supply.
-- 
David Empson
dempson@actrix.gen.nz