G3 drop in replacement for 603?

dpaanlka

macrumors 601
Original poster
Nov 16, 2004
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Illinois
Considering that the 750 was a direct descendant of the 603 line of processors, how backwards compatbile are they? Is it possible to unsolder a 603 chip from a motherboard and solder in its place an early 750, thus turning it into a low clocked G3 without making any other changes or modifications? Could an early 750 processor be a literal "drop-in" replacement on a "non upgradeable" 603 system?

And where would I be able to find information about 750 chips with the same exact size and pin count as my 603 chip? From Freescale? IBM?

I'm not asking whether or not its worth it, just whether it can be done.
 

TheSilencer

macrumors regular
May 27, 2007
111
0
Here is the Datasheet for the PPC 740/750 and 603(e). Looks like they have the same pin count as a 603(e) but I have not compared all pinout informations, but looks similar to me for now.

PPC 740/750, page 27 pin assignments. (IBM)
http://www-01.ibm.com/chips/techlib/techlib.nsf/techdocs/04D8DD112C160E0887256A0900615D50

PPC 603, page 14 pin assignments (Freescale)
http://www.freescale.com/files/32bit/doc/data_sheet/MPC603EC.pdf

However, it could be that the upgraded system does not "see" the new CPU correctly because the Firmware has - maybe - not the correct CPU ID stored. With some luck it should work, but system information could show a wrong CPU information, in bad case, it just does not work or the whole thing explodes. :rolleyes: :D
 

Sun Baked

macrumors G5
May 19, 2002
14,874
57
The bus is the same, or the G3 provides a mode for running on the older 60x bus.

An upgrade card can be applied to a cache slot, which is on the FSB.

If you find one of these upgrade cards, the current G3 should be a drop in replacement for the older G3s -- with a few pinout changes.
 

ReanimationLP

macrumors 68030
Jan 8, 2005
2,765
26
On the moon.
Only problem I see is how its all a ball grid array solder. If you have the very expensive equipment or access to it, I'm sure its possible.
 

dpaanlka

macrumors 601
Original poster
Nov 16, 2004
4,869
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Illinois
Only problem I see is how its all a ball grid array solder. If you have the very expensive equipment or access to it, I'm sure its possible.
I think I just might, to be honest. I'm considering attempting this on a few spare PowerBook Duo 2300c motherboards. Did the processors differ in size from the above linked documents on notebook motherboards?
 

TheSilencer

macrumors regular
May 27, 2007
111
0
I think I just might, to be honest. I'm considering attempting this on a few spare PowerBook Duo 2300c motherboards. Did the processors differ in size from the above linked documents on notebook motherboards?
Not sure about that... IBM says that the 603 was special designed for low power consumption. The 604 was designed for workstations and the 750 didn´t have a mobile version afaik but could be that the 740 one was for mobile use and the 750 for workstations but Apple used only 750 chips in their products I believe.

One of the problems could be the CPU soldering, this differs from desktop to mobile computers or even within a series of a product:

wire package 100MHz 603
http://upload.wikimedia.org/wikipedia/commons/d/d7/XPC603EFE100LF_01.jpg

bga package 200MHz 603
http://upload.wikimedia.org/wikipedia/commons/a/a1/XPC603PRX200LC_01.jpg
 

Anonymous Freak

macrumors 603
Dec 12, 2002
5,128
442
Cascadia
I think I just might, to be honest. I'm considering attempting this on a few spare PowerBook Duo 2300c motherboards. Did the processors differ in size from the above linked documents on notebook motherboards?
Ooooh... A G3 Duo. Then you just need to upgrade the screen to the 800x600 screen from the 5300ce, and find a way to cram more than 96 MB of RAM in there, and you'll be set! :p

I just wish my Duo 2300c hadn't died on me.
 

dpaanlka

macrumors 601
Original poster
Nov 16, 2004
4,869
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Illinois
Ooooh... A G3 Duo. Then you just need to upgrade the screen to the 800x600 screen from the 5300ce, and find a way to cram more than 96 MB of RAM in there, and you'll be set! :p
I don't think that's even possible? And I thought my Duo was maxed out at 56 MB. 2400cs are the ones that can take 96 MB.