View Full Version : Revision B or C ROM upgrade for G3?

03-12-2001, 07:26 AM

I read somewhere about upgrade ROM modules to be able to add
IDE slave support to an early (revision A) beige Desktop G3.

Do you sell these modules or do you know who does?

Are there any other possibilities for adding an extra drive without taking up one of the valuable PCI slots? Will the G3 accept internal SCSI (I already have external SCSI devices attached: Zip and CD-R)?

Will any processor upgrades solve the revision problem?

Any information is highly appreciated

03-12-2001, 12:44 PM
Louie is our resident Beige G3 Rom number master. I will go ahead and quote the almighty :

"Look in your Apple System Profiler on the first page. Look for the ROM subversion. If it's v4.0F2, you have a Rev A. If it's V 4.5F1/F2 it's a Rev B."

Rev A and B are the only actual variants. I think the Rev C is a myth. They are in short supply. Not sure about a current source. Not here. SmallDog used to, as did some others. Most are out of stock. Someone who has been searching for one should be in soon with a redirect.

Here is a diagramn of your motherboard. You have internal IDE and SCSI. So you can always add in more SCSI drives. So long as you assign ID's and terminate properly. That is another issure, if you need help. Many of us can step you through. No processor upgrades will solve the ROM limitations, as they do not change/update the ROM programming. You might look around for a dead (or not) motherboard of a later revision and swap out the ROM. That's my 2 cents.

03-12-2001, 12:45 PM
Ooops. Forgot to post the link to your mobo!!!!

03-12-2001, 02:47 PM
You can add an a SCSI-2 HD without adding a PCI card, but it will be dog-slow since the built-in SCSI controller, NCR 53c96, which is limited to 5 MB/sec.

Rev B ROMs have become very hard to find.

03-14-2001, 03:39 AM
the mythical Rev C ROM does exist.

in fact, it should be possible to find an actual part number in a current Service Source.

03-15-2001, 05:49 AM
ha ha ha ha. i have been in search of the elusive revision b rom (or the legendary revision c) for some time now. ive seen two for sale. one was bundled with a copper g3 zif on ebay (the guy didnt know what he had!) and the other, also on ebay, went for $82.

i was out bid on that last one. for the amount of time ive spent searching, it was probably would have been justified to pay $82. except that i am also looking for an a/v personality card and an internal modem. for the combined price of these components on the odd occasion i have found them, i could nearly buy a refurbished beige minitower that has all that, in addition to the rage pro gpu, on the motherboard, as well as whatever happens to be bundled with it. i have tried to find the service part number for them, but that has also been pretty fruitless. i have only been able to find them for sale when already installed on a motherboard-and usually only if you have a revision motherboard that you will trade in for the replacement. and even then, the cost is around the same as a refurbished computer. so if you come across a source of them for a reasonable price, buy them all cause i can guarantee youll turn a profit. also send me an email and ill buy one from you.

03-15-2001, 05:20 PM
Jorge has a Service Source. If we can pry him away from his new Ti, maybe he'll look up the part numbers for you.


03-16-2001, 12:19 AM
that would be most appreciated.

03-16-2001, 12:29 PM
Thanks for the help. I'll try to see if I can locate some "dead" G3's.

Which machines could have the revision B ROM? All Blue and Whites also?

03-16-2001, 03:26 PM
revision b roms are in any beige g3 that shipped with a processor faster than 300 mhz. I dont recall, but i think the 300mhz machines might also have the revision b rom. 233 and 266 definately do not.

03-17-2001, 03:28 AM
talked to a guy that has a beige g3 produced in the last week of beige production (he claims), says his rom revision is $77D.45f2. in october 1998.

[This message has been edited by batmantis00 (edited 17 March 2001).]

03-18-2001, 05:00 AM
before posting the following, let me state that I will defer to Louie, whose scholarship on this particular Mac exceeds my own. My understanding is that ROM $77D.40F2 corresponds to Rev 1, $77D.45F1 corresponds to Rev 2, and $77D.45F2 corresponds to Rev 3 (or, Rev A thru C, if you prefer).

the thing is, Apple's technical docs are confusing here, as there is no doubt that some beige G3 shipped with Rev 3 ROM....but was the same ROM rev used in Yosemite? Apple says it was. And that's what's kicking my ass this week.

if I'm not mistaken, the very first revision of Yose did not support IDE slaves, a problem which was later fixed in Rev B's and later. And this, too, is inconsistent, as the Rev 3 ROM in Gossamer was very good, and absolutely supported IDE masters and slaves.

anyway. Now you know what I am thinking about as I sit, nodding and drooling, in my chair at 4AM on a Saturday night.


03-18-2001, 06:56 AM
yeah, i thought yose wasnt that far removed from gossamer, but then the more i thought about it, the more i thought i was an idoit, cause those two boards dont sound that similar. the pci slots are different bit/speed, we have firewire and usb, but no adb or serial, no perch card, ata/66, no scsi.

and i realize i dont understand what the whole new world thing means if yosemite has a rom i ccould pull out and put in a beige. and if i can, why cant the rom flash that i know i installed on a friends b&w flash a beige, or what happened if you put it in the baige after it was flashed, or are these even the same rom. and if the last apple rom revision for the board had the no-g4 thing that needs a thirdparty patch to install upgrades, then how did the g4 in yikes function.

speaking of drooling at 4 in the morning....course its only 2 here.

and not that its in anyway related, but ive noticed in the past ten or twenty minutes that my cursor is jiggling. it wobbles back and forth about one pixel worth. eventually it settles one pixel to the left of where it started. i can click a button without touching the trackball and it starts again, ostensibly migrating all the way across the screen. stupid mouse.

03-18-2001, 11:03 AM
One might make the observation that bG3's have no SCSI either. My red-faced realization of the 5MB/sec limitation of the internal bus (via Louie's earlier post on this thread) came *after* I had ordered a GD SCSI cable and an UltraPlex for my new bG3 266 MT. http://macgurus.com/infopop/emoticons/icon_redface.gif

There were other surprises, as well. I had expected it to most likely have the AV perch card and be Rev A, or at best Rev B. Well, the actual box has no AV and has the Rev C ROM ($77D.4572). I don't think either the original owner or the seller (two different people) changed either the perch card or the ROM. The seller was a local mac guy (local to the owner) who replced the IDE hdd (w/a Western Dig 20GB) and stuck in the cheapest 256 RAM stick he could find. He also left out the damned SCSI cable! Anyway, my gut feeling is that this box was from an assembly run of 300 or 333 MT's in which they ran out of the right ZIFs. "Make it a 266, and off she goes."

In spite of the "innovations" that the bG3 line represented for Apple (ZIFs, IDE, ATI vid, etc), when I was giving my gossamer mobo the first up-close look--and noticed that voltage regulator sticking up from the mobo like a spare tire on a Model T Ford--I realize what a quirky machine I've gotten myself into. But, as John Paul Jones said, "I have not yet begun to upgrade!"

The actual point of this windy post is that my experience, like that of the guy bat talked to, suggests that the component use in the production of these boxes was, at times anyway, fluid.

03-18-2001, 05:37 PM
Hey guys!

All of you are screwed up! I've explaned this Rev A/Rev B thing so many times on these forums that it would make a dog barf. There was no Rev C! The type of Perch Card can not be related to Rev's. There were Rev A's with A/V cards. It depended on which PERCH card was ordered.

I've uploaded the revised Apple Developer Note that explains everything there is about the Beige G3 here ftp://ftp.macgurus.com//ftp/apple_stuff/ . The document is "PowerMac_G3.pdf". Read it and quit writing erroneous rumors.

03-18-2001, 07:57 PM
i thought i was screwed up. i just needed someone to knock some sense into me. thanks louie.

03-18-2001, 08:50 PM
yep. me too. Thanks Louie, and also for posting that pdf.

03-18-2001, 09:55 PM
You're welcome. Commit that document to memory!

03-18-2001, 11:50 PM
yeah, i should be able to recite it by memory by morning. lol