Re: ROM 00 to ROM 01 upgrade

[a_specto@alcor.concordia.ca (Mitchell Spector)]

"Steve Q" <sqnospam@superbio.notrash> wrote:

>I'm not much of an electronics person, but a good friend -is.-  Let's say
>that I'd like to copy these ROM 01 upgrade chips, so that if I'm ever in
>this predicament again, I can simply roll my own (and for personal use...I'm

    From what I recall of past discussions, it wouldn't be possible due to
the lack of existence of an EPROM being available in the needed pin
package/memory size (128K, but in a 28-pin DIP). You'd need to rig up
a socket adapter, and to this day, I've never heard of it being done.

    Your best bet is just keeping a ROM 0 as-is (some people seek these
just as an obscure collection piece) and simply pick up a base ROM 01
box or motherboard. They're generally $5 or less these days--I even saw
some sell on eBay for 1 cent recently!

>certainly not looking to pee on anybody's lawyers or anything like that).

    Incidentally, Apple stopped offering the free ROM upgrade as of
March 31, 1995 and it's undoubtedly not available any longer even
as a special part order (Apple released a press release several years 
back saying they were no longer obligated to carry parts or do repairs 
to products less recent than the mid/late 90's). 

    For that reason I doubt even Apple would object to you burning 
your own ROMs for upgrade purposes (obviously to systems you
already own). Assuming you found a way to do it...

>PS:  Is there any way to identify a ROM 00 versus a ROM 01 versus a ROM 03
>simply by looking at the case (assuming motherboards haven't been
>transplanted)?

    If the case is closed (and sealed with that screw in the back-middle)
you could look at the serial number on the bottom of the case. It's not
an infallible method however, the oldest IIgs motherboard fits perfectly 
in the newest IIgs case (and visa-versa). If a dealer or user ever did a
ROM or motherboard swap, case markings are meaningless.

    Assuming you do come across an unaltered system from the day it
was bought, you can use this serial range to help guide you:
                   
- earliest        <------------------- ROM 00 + faulty VGC
- ....etc
- 703xxxxxx
- 704xxxxxx 
---------------------------------------------------------
- 705xxxxxx  <--------------------ROM 00 
- 706xxxxxx
- ....etc
- 723xxxxxx
- 724xxxxxx
----------------------------------------------------------
- 725xxxxxx <------------------- ROM 01
- 726xxxxxx
-.....etc

    Off hand I don't know the serial number range for the ROM 3, and all IIgs
cases had the same model number regardless of which motherboard was in
the case (A2S6000). My ROM 3, from early 1990, starts with this number if it
helps: "013xxxxx". The IIgs I bought in late 1987 started with "815xxxx". 

>The classic method is to boot the system, but once in
>awhile, I find systems that are sold by organizations that won't let you
>fire them up inside the place (even though they allow returns).  I'd guess
>that the answer is "No," other than maybe looking for "1989" on the ROM 03,
>but in case someone knows a trick I don't know, I'd love to hear it.  Thanks
>again.

    The best way to tell is opening the case and looking inside. I can
instantly spot a ROM 00, 01 or 3 motherboard, even glancing at a 
fuzzy photo image.

ROM 00 motherboard: 

- White sticker on ROM chip
- ROM part number suffix is "-A" , and "86" is last copyrighted year

ROM 01 motherboard:

- Part number silked-screened on ROM chip (no sticker)
- ROM part number suffix is "-B", and "87" is last copyrighted year
 
ROM 3 motherboard:

- Two ROM chips side by side (instead of one)
- Eight RAM chips (instead of four)
- Battery in snap-case, next to slot-1 (visible with powersupply installed)
- 'Sound RAM' and 'Standard RAM' arranged in a straight line
- "Apple IIGS" printed vertically on right (instead of "//GS" horizontally)
- Ensoniq and VGC chip soldered directly to motherboard (no socket) 
- Slots labeled "J1", "J2", etc in small print (not large plain numbers)
- Board color a darker green (in some cases, with gold colored pathways)

    I could go on (i.e. CYA, newer ADB microcontroller, 'S1' jumper pins,
manufacturing date codes and so on) but once you spot the first two
or three visual signs above, you'll already know it's a ROM 3 board
(well, technically "The Apple IIGS with 1 Megabyte of RAM" board
as Apple officially named it).

    As a side note to the above, there really is no such thing as a ROM '00'
and '01' motherboard. Only one board was produced (with 256K RAM 
installed) and you could plug either ROM chip into it. Also, all three
firmware revisions came as masked ROMs (the only exception was an 
early leaked beta copy of the ROM 3 which came on a pair of EPROMs).
Hmm,, speaking of that, did anyone ever confirm whether there had been 
a second leaked version of the ROM 3 firmware? Several months back
someone mentioned having EPROMs with 341-xxxx part numbers never 
before heard of.

Mitchell Spector
a_specto@alcor.concordia.ca