[helloHuman]

Hello...
Just got my 15" MacBook Pro... (OS X 10.4.10) and I'm trying to sync up all my external toys that I used with my older 12" Powerbook.

When I connected my Presonus Firebox external audio device to the Firewire 400 port on my MBP, I noticed that it didn't work unless I used the optional Presonus powerplug wallwart. I thought this was strange, because I don't need that power source when I used this same device with my AMD PC tower or my older Powerbook G4 12" - they powered this device with bus power only.

Is there something wrong with my MBP FW 400 port?
Do I not have a preference turned on?


I don't have another firewire device to test, other than an external HD, which does need external power....

any help or suggestions would cooool...

thanks!

[mfbernstein]

Read this. Basically, it requires more on startup than the bus provides. After that though, you can disconnect the AC adapter.

[helloHuman]

dang... you nailed it.
thanks very much!!

[mduell]

The Firewire spec allows for up to 45W (9A @ 5V), but Apple's (and most other) computers have a much lower limit. Macs range from 15W (PowerMacs/Mac Pros) to a handful of watts (iBook, MacBook, etc), so I'd guess the MBP provides a tad less than your PB did.