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mrmarcuswms
March 10th, 2008, 04:43 PM
Hello everyone. I am new to collecting vintage computers and I came across a Apple II GS at a yard sale for $5.00 bucks. I have been doing some research and I can't seem to find a clear answer on how to determine if it is a ROM 1 or ROM 3. Can anyone help?

ahm
March 10th, 2008, 04:58 PM
I can't seem to find a clear answer on how to determine if it is a ROM 1 or ROM 3. Can anyone help?

Couldn't find anything in Wikipedia (http://en.wikipedia.org/wiki/Apple_IIGS#Revision_history)?

mrmarcuswms
March 10th, 2008, 05:24 PM
I would rather find the info in somewhere beside wikipedia. I did find some info @ http://www.1000bit.net/support/manuali/apple/technotes/iigs/tn.iigs.026.html

david__schmidt
March 10th, 2008, 05:32 PM
I have been doing some research and I can't seem to find a clear answer on how to determine if it is a ROM 1 or ROM 3. Can anyone help?
Turn it on. The ROM version is part of the initial splash screen. If there is no revision number... then it's ROM 0.

Sharkonwheels
March 10th, 2008, 08:26 PM
Isn't a ROM 3, the later version?
1MB RAM on the motherboard?

Really easy to tell - older mainboard has 4 chips, newer has 8 chips, right?
Near the front, a little off center to the right, correct?

This, to me, looks like a ROM 00 or 01:
http://www.kpsurplus.com/images/8ea7b7b5a8b827d4b02e2d7df2935e069b789dcc.jpg

And THIS like a ROM 03:
http://chester.blog.br/img/micros/appleiigs/01_Motherboard%20IIGS.jpg

As I recall, you could upgrade the ROM in a ROM 00 to a ROM 01, but a ROM 03 was a totally different machine, even that the ROM space was twice as big -upped from 128KB to 256KB in the ROM 03 model.

In the first picture above, there are 4 chips near the white socket.
In the second picture, there are 8 chips. I believe in photo 2, of the ROM 03, those were 44256's, 256k x 4-bit, each pair being 256KB, totalling 1Mb RAM.

On the earlier board, first photo, I believe it is (4) 4464's (64kbit x 4) totalling 128KB, plus the 128KB for II classic mode (front left corner on both machines)

Because of the extra 128kb, the 1MB RAM is also known as the 1.125MB RAM model, and the earlier as the 256kb model.

Apple, with later ROM 01 production machines, added a RAM card, with 256Kb RAM, and sold the unit as a 512KB IIgs.

Obviously, the most desirable for *USE* is the ROM 03. FOr gaming, I believe there are some games which do not like the ROM 03 machine, so die-hard IIgs lovers have both - 1 for gaming, and one to mod up as a nice machine.

T

mrmarcuswms
March 12th, 2008, 03:34 AM
My MB looks just like yours for ROM 03 but when I boot it it says ROM 01 on the splash screen. I guess I'll call it ROM 01. It also has an memory expansion card. I will post a picture later.

Sharkonwheels
March 12th, 2008, 01:06 PM
A ROM1 is a 128KB ROM, and a ROM3 is (2) 128KB ROMs, so yours can't be a ROM1 *AND* have the later board - you would have 1 empty ROM socket, if it would even work.

In the 2nd picture I attached above, just to the right of the white socket is the main RAM. Just to the right of that is the (2) PROMs.

In the 1st picture, below the white socket near center, there are 2 chips - the right one is the PROM chip. The ram is to the right of that, 4 chips in a row.


T

mrmarcuswms
March 12th, 2008, 06:00 PM
A ROM1 is a 128KB ROM, and a ROM3 is (2) 128KB ROMs, so yours can't be a ROM1 *AND* have the later board - you would have 1 empty ROM socket, if it would even work.

In the 2nd picture I attached above, just to the right of the white socket is the main RAM. Just to the right of that is the (2) PROMs.

In the 1st picture, below the white socket near center, there are 2 chips - the right one is the PROM chip. The ram is to the right of that, 4 chips in a row.


T

Your right, I looked at the picture again and it looks like your picture 1. Thanks for the help. You've been very helpful. Thanks

Sharkonwheels
March 12th, 2008, 07:12 PM
Your right, I looked at the picture again and it looks like your picture 1. Thanks for the help. You've been very helpful. Thanks

Marcus, that's what we're all here for... We all help each other out.


T