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View Full Version : Powermac G4 PCI Firewire... What the...




Zoetrap
Jun 17, 2011, 03:15 AM
Now to something really odd...

I recently installed a new Firewire PCI card (NEC Chipset) in my old Powermac G4 Yikes machine. Everything worked perfectly right away.

Later I connected a firewire cable directly from my Macbook Pro (Firewire 800 - 400 cable) to do some remote desktop stuff and transfer some files. Everything worked fine. After I was done I powered down the Powermac.

Now to the interesting part. When the powermac had powered down I noticed that the 120mm fan inside it was still spinning. Kinda strange I thought, since the machine was completely turned off.

So I disconnected the power cord... and the fan was still running!!

I thought there was some kind of black magic going on...

Well, after a bit of tinkering I found out that the powermac was somehow gettiing power through the firewire cable! Enough power to start the 120mm fan apparently. I later reproduced the same thing with the Firewire PCI card installed in an older B&W G3.

I still don't know what to think of this... is there some sort of flaw in the Yosemite motherboard design or the Powermac PSUs? Is there something fishy with the firewire card? Is the computer SUPPOSED to do this (which I kinda doubt)?

Anyone with similar experiences or clues regarding this?



max••
Jun 17, 2011, 07:41 AM
Was the macbook still connected when the fan was spinning? i had a powered usb hub on my macmini some time ago that kept the power light on after i powered it down

Zoetrap
Jun 17, 2011, 08:00 AM
Yes, the Firewire cable was connected between the Powermac and the Macbook.

max••
Jun 17, 2011, 08:17 AM
Yes, the Firewire cable was connected between the Powermac and the Macbook.

I wouldn't worry about it then, probably just the way the power is routed between the psu and the pci slots