Re: How can clueless seller tell if IIgs is a ROM 3?

[Mitchell Spector <mitch2gs@hotmail.com>]

Linards Ticmanis <ticmanis@gmx.de> wrote:

>is there some easy-to-discern and unambiguous outward physical
>difference between a ROM 3 and a ROM 0/1 Apple IIgs
>
>a) that can be picked out in blurry photos, or
>
>b) that I can ask an eBay seller to check?
>
>I'm referring to something that does not require powering on (or even
>opening up) the unit.

    Yes, but it requires opening the top lid and having a quick 
visual glance at the motherboard. I can spot one in seconds,
even if the image is heavily blurred, looking at one specific 
clue at the center of the board:

- 2 masked ROM chips, directly adjacent to CPU (versus only 1)
- 8 memory chips grouped just above them (versus only 4)

Also noticeable with closer inspection, for those interested...
(although really unnecessary once you use the above clue)

o  Silk-screened model name printed as "Apple IIgs" *vertically* 
along the left hand side, original board horizontally across and
written as "Apple //GS".

o  Socketed lithium battery visible at the top left corner, next 
to the powersupply (hidden underneath and soldered in
on the original board).

o  DOC RAM (bottom left corner) is perfectly in-line with Slow 
RAM, whereas it's spaced apart and higher up on original.

o "S1" jumper pins (Control Panel disable) near center of board.

o  Ensoniq and VGC soldered directly to board

o  Apple IIe keyboard, numeric pad and powersupply solder 
pads (or pin connectors themselves) *NOT* present.

o  Slot labeling is much smaller, and printed as "J1", "J2", etc.

o CYA chip (instead of FPI), newer ADB microcontroller chip.

o  ROM 3 boards have traces and pathways that are painted 
gold or dark pine-green.

>Is there any such mark, for example a different arrangement of I/O ports
>on the back side of the machine? I've never had access to a real IIgs
>before.

    No, nothing at all. They appear completely identical from 
the outside, even if the motherboard was changed.

    There is the serial number on the bottom, however it 
cannot be used as a fool-proof method as the boards
could be easily swapped. I believe boards which serial
number started with 6xxxx, 7xxxx or 8xxxx (possibly 9?)
shipped with the original motherboard.

    There is also a leaked beta firmware found in some
ROM 3 motherboards, these used EPROMs with less
pins instead of the typical masked ROMs. Fairly 
uncommon, so hardly worth mentioning.

    Still looking for a replacement ROM 3 board for my
Apple IIgs system. Apparently my current one is the
reason for my severe ZipGS instabilities. :(

Mitchell Spector