At 08:57 -0400 05/27/2002, Tom & Lisa P wrote: >>Mad Dog, you ever have any luck soldering on BGAs? Actually, I'm not >>yet sure the thing is pin compatible with older CPUs. IBM doesn't >>appear to have a data sheet on their site, only marketing type stuff >>so far. Odd, since they claim it's sampling in early 2002. > >SOrry, I never got past the theoretical stage. While I think I can >get a BGA off, I dont know how I >would put a BGA on....... > >Plus, I thought these new chips had enough electrical differences to >prevent thier easy use on the upgrade market.
>Mad Dog The new G4s which have bus ratios above 9X (up to 16X I think) have problems because they have integrated L2 caches and a controller for an external L3 cache. This creates some issues with how to handle the cache on older machines. However, there doesn't appear to be any such issue with this new G3 chip. It just ahs the L2 cache, though it's integrated inside the chip. The chip does run on a lower voltage, but the PCM (Processor/Cache Module) reference design has provisions and codes to indicate the lower voltages already built in. So the voltage regulators on the Beige G3 and on the ZIF Carrier cards should be capable of delivering the lower voltage provided the designers followed the reference design. The biggest challenge (other than physically soldering the chip down) would probably be that the PCM has four pins for bus ratio and the 750FX has five pins for bus ratio. Somehow, one would have to get a jumper or something to that fifth pin, which may not be accessible. It is also possible that the pins are arranged in a completely different pattern, in which case a new board would be needed. The 750FX is so new though, that the document with the pinout isn't on IBM's web site yet. You might hunt down a document called MPCPCMEC.pdf on Motorola's SPS site. It appears to be the specs for the G3 ZIF module. IBM apparently had a similar document but I have not been able to find it. The only reference I found said to check ftp.austin.ibm.com and IBM's ftp sites all appear to be gone. I was hoping to find something with an actual board layout (PCB design), and I suspect that IBM's reference design might have contained that. One interesting thing about the contents of MPCPCMEC.pdf is that it implies that these PCMs (better known to us as ZIF processor modules) can be ordered directly from Motorola as a part that Motorola builds. I would guess this is where OWC gets their unbranded ZIFs. They're likely ordering them from Motorola (or IBM?) in quantity. Folks like XLR8 would have to build their own because they have some custom modifications, though, perhaps, they can just order the modifications from the department at IBM or Motorola that builds these things. So, if I could find the info from IBM which is analogous to MPCPCMEC.pdf from Motorola, I might be able to come up with a part number for ZIFs made by IBM. On Arrow Electronics web site (humongous electronics distributer) a search on PPC750 turns up several line items labeled "IBMPPC750....Apple Sidewinder". I'm guessing that was IBM's ZIF card. All of those items are listed as out of stock. Once I've got a part number, I can hunt down pricing and availability. I suspect that IBM just doesn't make ZIF cards anymore though. Jeff Walther -- SuperMacs is sponsored by <http://lowendmac.com/> and... Small Dog Electronics http://www.smalldog.com | Refurbished Drives | Service & Replacement Parts [EMAIL PROTECTED] | & CDRWs on Sale! | Support Low End Mac <http://lowendmac.com/lists/support.html> SuperMacs list info: <http://lowendmac.com/supermacs/list.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/supermacs%40mail.maclaunch.com/> Using a Mac? Free email & more at Applelinks! http://www.applelinks.com
