Welcome to the MacNN Forums.

beverson · Aug 14, 2005, 12:47 PM

I've been having the usual iSight/iPod/FW HDD power problems with my 12" PowerBook (and my 17" iMac before that). The FireWire hub on my Cinema Display is nice, but isn't helping. I have a configuration that works most of the time, but sometimes the iPod or a FW HD will freak out and spin down/up/down/up and I have to unplug it and hope I didn't lose any data. I know that PowerBooks and iMacs have relatively low FireWire bus power, which is contributing to the problem. So I'm now finally looking at powered FireWire hubs to help with this.

Question 1: What exactly is a FireWire "repeater?" This Belkin model is listed as a repeater, but their other hubs are not. The description seems to imply that this allows cabling to extend farther, but does that also mean it will "power" devices on the hub too? I've read in some threads that even powered hubs don't have enough bus power to charge an iPod or run an iSight, etc. Will a hub like this work better than just a "regular" powered hub? Anyone have experience with this device?

Question 2: What's the best configuration I should use? I currently have only one FW port on the PowerBook and two FW ports on the Cinema Display's built-in hub. I have a FW iPod, the iSight, and (currently) two FW HDDs (one is also USB 2, but I want to avoid using that if possible). I'm thinking that it would be ideal if I could plug the display's hub into the PB, the iSight into one port on the display, plug a new powered hub into the other display port, and then run everything else off the powered hub. Or should I skip the display and just use the powered hub plugged directly into the PB? (That Belkin has 6 ports, I think).

Cadaver · Aug 14, 2005, 04:00 PM

You shouldn't have too much of a problem if your hard drives are self-powered (plug in to the wall AC). You'll run in to too much power drain if they're bus powered. Either way, you should be able to buy AC adapters for your hard drives.

If you can, I'd then plug the monitor in to the FW port of your PowerBook, the iSight in to one of the monitor's ports, and then daisy chain the two HDs and the iPod off the other (presuming that your HDs have two ports each on the back).

You could also consider plugging in your iPod via USB, assuming you have a USB-capable iPod. This would further reduce the need for FireWire bus power.

Either way, I wouldn't recommend trying to run more than one bus-powered device (especially a hard drive) off any one FireWire chain. And be careful plugging your iSight in to the daisy-chain port of a hard drive - I'd heard of people having power draw problems this way.

I have an iSight plugged in to one port of my Cinema Display, and an AC-powered hard drive + AC-powered DVD-RW on the other port. All essentially connected to the one FW400 port on the back of my G5. No trouble.

beverson · Aug 14, 2005, 04:24 PM

Both of my HDDs are self-powered, but sometimes the bus still doesn't have enough juice. One in particular has regular problems and it works more reliably if I just plug it directly into the PowerBook and nothing else daisy-chained off it (as opposed to everything running through the, I think, non-powered hub in the Cinema Display).

Cadaver · Aug 14, 2005, 09:09 PM

Sounds more like a problem with your drives' cases. Theoretically you should be able to daisy chain 63 devices off one FireWire bus.

beverson · Aug 14, 2005, 10:08 PM

Originally Posted by Cadaver

Sounds more like a problem with your drives' cases. Theoretically you should be able to daisy chain 63 devices off one FireWire bus.

No offense, but I don't think there's any possible way to do that with the low power on a PowerBook's or iBook's FireWire bus, especially the 12" PowerBook (15" or 17" might be different, I dunno). Even for powered devices, it just doesn't have the juice. And then you throw the iSight into the mix?

I know, I could just plug in the iSight only when I use it. And that's what I've been doing. But I'd like to try and work around that if possible.

Cadaver · Aug 17, 2005, 08:54 PM

If you're having that much of a bus power issue (though I've not seen it on any of my machines), you could always add this to the mix: http://fwdepot.com/thestore/product_...roducts_id/372

beverson · Aug 18, 2005, 02:00 AM

Originally Posted by Cadaver

If you're having that much of a bus power issue (though I've not seen it on any of my machines), you could always add this to the mix: http://fwdepot.com/thestore/product_...roducts_id/372

Hey, that's a neat little gadget. I might have to pick up one of those.