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G3 B&W schematics

P

powermax

6502
Hi crews,

did anyone ever see the schematics for the Power Macintosh G3 B&W aka Yosemite?
I was able to spot schematics for some Power Macintoshes on this forum.
There is a page out here that offers schematics for PM G3 Beige and some G4 Macs as well.
Unfortunately, no schematics for Yosemite so far.
I'd like clarify some questions and to complete emulation for this machine in DingusPPC.

Thank you in advance!
 
Apple has an archive at Stanford which includes most or all of their product schematics but this is kept private. So, do they exist? Yes. Will they appear? Probably not.
 
Arbee said:
You could just ask :cool:
Click to expand...

Oh thats Awesome! theres very few schematics out there for the later Apple desktops like this! already been quite interesting to go through at a first pass, for example there is a brief mention of the "Max" CPU on the VRM VID settings, which of course, Max being the code name for the G4 CPU, so they where indeed already working on the G4 even then, which I had long suspected the G3 blue and white was used in G4 development since I notice that if you install a G4 7400 into a G3 blue and white, it does ID the CPU as "PowerPC Max" so it obviously recognises it rather then give it the generic "PowerPC 60?" name

and the other interesting one is to see there was a "production" CPU jumper block for a 500Mhz CPU configuration, but there never was ever a 500Mhz G3 blue and white, imagine finding that mythical red jumper block :) and other things like that, for example I see there is an option listed for a 32MB Rage 128, but no such card ever did end up shipping (they where all 16MB)

I have to ask, do you happen to have schematics for the Later Rev 2 G3 blue and white or the G4 Yikes! it would be interesting to see what the fine detailed differences are between all the Yosemite based boards are

EDIT: actually I think the schematics might indeed be for Rev B? I note the PCB part number in the schematic listed as 820-1049 although it still calls for the older CMD646 Variant, maybe there where late Rev A's with revised PCBs?

IIRC 820-0987 is Rev A G3 Blue and White board, and 820-1086 is G4 Yikes!

also also, if you dont mind me asking, but you dont happen to have schematics for any of the Apple G4 CPU cards do the ones used on the Sawtooth and later PowerMacs? or anything like iMac G3 Tray loader CPU card schematics or PowerBook G3 Pismo CPU card schematics? :)
 
Last edited:
LightBulbFun said:
I note the PCB part number in the schematic listed as 820-1049 although it still calls for the older CMD646 Variant, maybe there where late Rev A's with revised PCBs?
Click to expand...
nvm ignore this bit, although the older varient is mentioned here and there, if you scroll down to the BOM it calls for the later -402, variant, so this is indeed schematics for the Rev C motherboard used in the Revision B G3 Blue and white :)

and this little snippet is quite interesting, because I have had several Rev A G3 Blue and white's with early motherboards, they have always been very cantankerous especially when it came to RAM (often times I would have to shuffle or swap DIMMs about to get a system to boot etc) I wonder if this might be the reason they are so touchy?

1724994893326.png
 
LightBulbFun said:
nvm ignore this bit, although the older varient is mentioned here and there, if you scroll down to the BOM it calls for the later -402, variant, so this is indeed schematics for the Rev C motherboard used in the Revision B G3 Blue and white :)
Click to expand...

It's written in big as a watermark on the first page that it is the Rev-C. ;)

1725023298400.png
 
zefrenchtoon said:
It's written in big as a watermark on the first page that it is the Rev-C. ;)

View attachment 77724
Click to expand...
Yeah I see that :) but what I mean is, there where 2 distinct revisions of the whole G3 Blue and white Machine, the Rev A machines and the Rev B machines, and these Rev B machines had revised motherboards (and other different things, for example Rev B G3 blue and whites have a different hard drive cage setup, and came with Rage 128's that had heatsinks fitted, where Rev A G3 Blue and white Rage 128's where heatsink-less)

looking at the schamtics, I think the Rev A motherboard revision never made it past PVT (Production verification testing) thus has never actually been seen so to speak, before it was re-spun into Rev B for actual start of production, of the Rev A G3 blue and white then when the Rev B G3 blue and whites where released, yet another motherboard revision was done the Rev C motherboard

so the motherboards and whole machine revisions are slightly out of step if that makes sense? :)

Arbee said:
The only other B&W G3 I have is the DVT, so earlier rather than later, and I don't have any G4s other than what @3lectr1cPPC has on MacDat.
Click to expand...

no problems! I really appreciate you sharing the G3 schematics in themselves it is really awesome how these are finally coming to light after all these years :)

it would be interesting to see those DVT schematics just to see how they compare to the production ones :)
 
LightBulbFun said:
Yeah I see that :) but what I mean is, there where 2 distinct revisions of the whole G3 Blue and white Machine, the Rev A machines and the Rev B machines, and these Rev B machines had revised motherboards (and other different things, for example Rev B G3 blue and whites have a different hard drive cage setup, and came with Rage 128's that had heatsinks fitted, where Rev A G3 Blue and white Rage 128's where heatsink-less)
Click to expand...
I know these details because my father had one of the first Rev A in France from its work at the university and I got a Yikes! from another university which should be very close to Rev B G3. 🤪
 
LightBulbFun said:
for example I see there is an option listed for a 32MB Rage 128
Click to expand...
This 32MB Rage 128 is also listed in the 'NDRV' too, I think they did exist on the PC side, so flashing one should not be that hard, but any Radeon is going to out preform it, so nobody ever bothered.

It was not until the Radeon 7000 PCI that we figured most of the flashing stuff out.

I actually ran across a page with a patched versions of ATI Flash to flash the Radeon 8500 first. That's really where all the card flashing took off from.

nVidia cards could be flashed, but known one knew how to edit the ROM's until some Sith sat down with a HexEditor and nothing but time.
 
Arbee said:
You could just ask :cool:
Click to expand...

Not to be too cheeky, but you wouldn't happen to have Trayloader iMac G3 schematics, would you?
I'm currently doing some CPU card modifications, and am running into issues that without those are becoming a bit of stabbing in the dark trying to resolve :-)
 
Arbee said:
The only other B&W G3 I have is the DVT, so earlier rather than later, and I don't have any G4s other than what @3lectr1cPPC has on MacDat.
Click to expand...

It's surprising that the said B&W G3 schematic doesn't reveal where the PRSNT pins of the PCI slots are connected to.
It seems there is no way for SW to obtain this information on this machine.

The predecessor of this MB - the Gossamer board - implements a system register that reflects the state of the PRSNT bits for all PCI slots.
All pre-G3 machines also have a board register attached to the Grand Central I/O controller.

Is the DVT schematic more specific on that?
 
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