As a grizzled veteran of working on the "Ultimate Road Apple", I can say that it did, indeed, use "one-off" RAM sticks. They were: 3.3v EDO un- buffered DIMMs. 2 slots could see 64mb DIMMs, the third slot could see no more than 32mb giving you a maximum of 160mb. The pin-outs were just off-set enough, that IF you DID manage to seat it in the slot of a 7500...say, you probably damaged the slot, the DIMM, or both! The 4400/7220 was and is a thoroughly HORRID excuse for a Macintosh! In my humble opinion. Mikie
> From: Jeff Walther <[EMAIL PROTECTED]> > Reply-To: "PCI PowerMacs" <[EMAIL PROTECTED]> > Date: Wed, 1 Sep 2004 09:08:12 -0500 > To: "PCI PowerMacs" <[EMAIL PROTECTED]> > Subject: Re: [PCI] RAM and PCI slots > > At 15:30 -0400 08/31/2004, PCI PowerMacs wrote: > >> From: Bruce Johnson <[EMAIL PROTECTED]> >> Date: Mon, 30 Aug 2004 14:47:32 -0700 > >> This is largely an accident of Apple's timing. Apple jumped on the DIMM >> bandwagon early, and settled on the 5V first generation DIMMS. > snip >> Apple never made any systems (afaik) with the 3.3V EDO DIMMS, bit went >> right to the PC66 SDRAM in the Beige G3's. > > I think that the 4400 used the 3.3V DIMMs but I'm not certain about > that. There was one oddball economy model that did, IIRC. > > >> From: <[EMAIL PROTECTED]> >> Date: Mon, 30 Aug 2004 23:13:58 -0400 > >> That is EXACTLY what I mean. Think about the typcal 168-pin DIMMs >> that you have seen used in PCI Macs. The word for them is "chunky." >> >> I purchased some 168-pin DIMMs that look just like the usual 5v FPM >> 168-pin DIMMs but they probably weigh about half as much. All of the >> chips on both sides of the DIMM are very, very thin. I'm away from >> home right now so I can't pop one out of the 9600 to check but I'm >> sure that they say 3.3v right on them, run at 60ns, and are >> designated IDT 74FCT 162244 APA. >> >> They work just fine in a 5v Macintosh environment. > > I think that you will find that there are voltage regulators (little > three pin component, looks like a minature TO-220 package) on those > DIMMs to reduce the supply voltage from 5V to 3.3V. Giving a chip > which is rated for a 3.3V supply voltage a 5V source is a *Bad Thing* > tm. > > As such, they will work in a 5V environment, but almost certainly not > in a machine that requires 3.3V--although they might. It depends on > the voltage regulator used. > > Jeff Walther > > -- > PCI-PowerMacs is sponsored by <http://lowendmac.com/> and... > > Small Dog Electronics http://www.smalldog.com | Refurbished Drives | > -- Sonnet & PowerLogix Upgrades - start at $169 | & CDRWs on Sale! | > > Support Low End Mac <http://lowendmac.com/lists/support.html> > > PCI-PowerMacs list info: <http://lowendmac.com/lists/pci-powermacs.shtml> > --> AOL users, remove "mailto:"; > Send list messages to: <mailto:[EMAIL PROTECTED]> > To unsubscribe, email: <mailto:[EMAIL PROTECTED]> > For digest mode, email: <mailto:[EMAIL PROTECTED]> > Subscription questions: <mailto:[EMAIL PROTECTED]> > Archive:<http://www.mail-archive.com/pci-powermacs%40mail.maclaunch.com/> > > Using a Mac? Free email & more at Applelinks! http://www.applelinks.com -- PCI-PowerMacs is sponsored by <http://lowendmac.com/> and... Small Dog Electronics http://www.smalldog.com | Refurbished Drives | -- Sonnet & PowerLogix Upgrades - start at $169 | & CDRWs on Sale! | Support Low End Mac <http://lowendmac.com/lists/support.html> PCI-PowerMacs list info: <http://lowendmac.com/lists/pci-powermacs.shtml> --> AOL users, remove "mailto:"; Send list messages to: <mailto:[EMAIL PROTECTED]> To unsubscribe, email: <mailto:[EMAIL PROTECTED]> For digest mode, email: <mailto:[EMAIL PROTECTED]> Subscription questions: <mailto:[EMAIL PROTECTED]> Archive:<http://www.mail-archive.com/pci-powermacs%40mail.maclaunch.com/> Using a Mac? Free email & more at Applelinks! http://www.applelinks.com
