PPC 6xx CPU-series PowerMac Information
Power Supplies
The A version PSU was also used in the 7600 and 7200 PowerMacs.
A common swap of the time was to replace the motherboard of the 7200
with that of the 7600 which allows more upgrade options. >>>>>>>>>>>>>>>>>>>>>>
There are the A, B and G versions of the very same desktop Mac PSU.
The A version has a 22 pin main connector and a 10 pin auxiliary
connector, and is for the 7500/8500/9500 series.
The B version has a 24 pin main connector and a 10 pin auxiliary
connector, and is for the 7300/8600/9600 series.
The G version has a 20 pin main connector and a no auxiliary connector,
and is for the Beige G3 series (with the jumper set to "Mac").
An ATX PSU is also used in the Beige G3 series (with the jumper set to
"PC").
The ubiquitous "7500 series" case will accommodate a 7200, 7500, 7300,
8500 or 8600 motherboard, with the appropriate selection of the PSU.
The "7500 series" case is even designed to accept the A-V I/O card of an
8500 or 8600, although on early examples you do have to drill out the
connector openings. On later examples these holes are already there, but
are covered by a dummy cover.
7200
As Peter mentioned, the 7200/120 has a peltier thermoelectric cooler
equiped heat sink. This heat shink has two wires to a plug which plugs
into pins on the motherboard near the CPU. So even if the special heat
sink is missing, the power socket will be present near the CPU. The
7200/120 (and the fast 8100 models) should not be operated without the
special heat sink attached and powered.
IBM only rated the PPC601 to 100 MHz. They supported operation up to
120MHz, but only if active cooling such as a Peltier element was provided.
Without the Peltier, those faster PPC601s will not operate for long,
assuming the machine boots at all.
Interestingly, the 7200s come equipped with either of two ROM versions
and I have not been able to discern any rhyme or reason to which speed
machines have which ROM versions. The earlier revision ROM is $77D.28F1
and the later is $77D.28F2. The latter is the version found in all the
x500 machines and related clones. I speculate that the earlier ROM may
have been associated with the ethernet problem many early 7200s
experienced, but that's just baseless speculation.
PPC 9xxx Info
The very early 9500s did indeed have plug-in ROM-DIMM cards.
Only the later 9500s and all 9600s had soldered ROMs.
Other models (7xxx and 8xxx) had a provision for a ROM-DIMM, but it was
never used. NEVER, ever.
ALL ANSes had plug-in ROM-DIMM cards. There was no provision for soldered
ROMs. It is a completely new motherboard and did not use a standard
7xxx/8xxx/9xxx CPU, although it DID use the dual Bandit chips which were
found in the 9500/9600.
The O.F. which was provided in an ANS ... and all ANSes have the same
ROM-DIMM ... is indeed different from those in 9500/9600 Macs.
It is NOT POSSIBLE to plug in a 9500 ROM-DIMM and thereby to get Mac
compatibility. There are TOO MANY other differences.
That, plus the ANS is hard-coded to preclude more than 512 MB of RAM,
although the prototype motherboard, the 9500, could support 1.5 GB.
An ANS will fail to POST of more than 512 MB is installed.
Therefore, the two maximum RAM configurations are 4 x 128 MB or 8 x 64 MB.
The standard RAM configurations are ... for ANS 500, 32 MB ... and ... for
ANS 700, 48 MB. The motherboard is, of course, the same, so 512 MB is the
maximum, PERIOD.
The A version PSU was also used in the 7600 and 7200 PowerMacs.
A common swap of the time was to replace the motherboard of the 7200
with that of the 7600 which allows more upgrade options. >>>>>>>>>>>>>>>>>>>>>>
There are the A, B and G versions of the very same desktop Mac PSU.
The A version has a 22 pin main connector and a 10 pin auxiliary
connector, and is for the 7500/8500/9500 series.
The B version has a 24 pin main connector and a 10 pin auxiliary
connector, and is for the 7300/8600/9600 series.
The G version has a 20 pin main connector and a no auxiliary connector,
and is for the Beige G3 series (with the jumper set to "Mac").
An ATX PSU is also used in the Beige G3 series (with the jumper set to
"PC").
The ubiquitous "7500 series" case will accommodate a 7200, 7500, 7300,
8500 or 8600 motherboard, with the appropriate selection of the PSU.
The "7500 series" case is even designed to accept the A-V I/O card of an
8500 or 8600, although on early examples you do have to drill out the
connector openings. On later examples these holes are already there, but
are covered by a dummy cover.
7200
As Peter mentioned, the 7200/120 has a peltier thermoelectric cooler
equiped heat sink. This heat shink has two wires to a plug which plugs
into pins on the motherboard near the CPU. So even if the special heat
sink is missing, the power socket will be present near the CPU. The
7200/120 (and the fast 8100 models) should not be operated without the
special heat sink attached and powered.
IBM only rated the PPC601 to 100 MHz. They supported operation up to
120MHz, but only if active cooling such as a Peltier element was provided.
Without the Peltier, those faster PPC601s will not operate for long,
assuming the machine boots at all.
Interestingly, the 7200s come equipped with either of two ROM versions
and I have not been able to discern any rhyme or reason to which speed
machines have which ROM versions. The earlier revision ROM is $77D.28F1
and the later is $77D.28F2. The latter is the version found in all the
x500 machines and related clones. I speculate that the earlier ROM may
have been associated with the ethernet problem many early 7200s
experienced, but that's just baseless speculation.
PPC 9xxx Info
The very early 9500s did indeed have plug-in ROM-DIMM cards.
Only the later 9500s and all 9600s had soldered ROMs.
Other models (7xxx and 8xxx) had a provision for a ROM-DIMM, but it was
never used. NEVER, ever.
ALL ANSes had plug-in ROM-DIMM cards. There was no provision for soldered
ROMs. It is a completely new motherboard and did not use a standard
7xxx/8xxx/9xxx CPU, although it DID use the dual Bandit chips which were
found in the 9500/9600.
The O.F. which was provided in an ANS ... and all ANSes have the same
ROM-DIMM ... is indeed different from those in 9500/9600 Macs.
It is NOT POSSIBLE to plug in a 9500 ROM-DIMM and thereby to get Mac
compatibility. There are TOO MANY other differences.
That, plus the ANS is hard-coded to preclude more than 512 MB of RAM,
although the prototype motherboard, the 9500, could support 1.5 GB.
An ANS will fail to POST of more than 512 MB is installed.
Therefore, the two maximum RAM configurations are 4 x 128 MB or 8 x 64 MB.
The standard RAM configurations are ... for ANS 500, 32 MB ... and ... for
ANS 700, 48 MB. The motherboard is, of course, the same, so 512 MB is the
maximum, PERIOD.