I've some troubles with Firewire and USB devices.
I've the following configuration:
Firewire:
1st connected (via Firewire 800 cable; without separate power supply): Daisy Cutter DC-SATA 800+ enclosure with two Firewire 800 ports and a 300 GB Samsung Spinpoint SATA hd drive
2nd connected (via the second Firewire 800 port on the Daisy Cutter enclosure; separate power supply): Pleiades SATA 3.5 " hard drive enclosure (Super S Combo with all interfaces) with a 300 GB HD.
Does anybody know about the bus power requirements if two hard drives are plugged in? Shouldn't it provide 1500 mA in total (as the first one only needs 850 mA at max and the second has its own power supply I do not understand the problem here!)? As the first drive does not have a separate power supply (and does not need one as power comes from the Firewire port) and the second drive has a separate power supply it should be ok to supply enough power for both devices. It's interesting if I unmount the first drive BEFORE the second drive the second drive begins to behave strange (and system seems to be crashed until I turn off the drive). Same if the first drive is turned on but not mounted and I then turn on second drive - the second drive behaves like it does not get enough power (but it has a separate power supply). If both drives are mounted it seems ok. Can somebody explain the technical background of the Firebus and why it does behave this way on my iMac? And does anybody know why the second drive is not recognized at all if the first drive in the chain is not turned on?
Same problem with USB:
1st port (inner side): Epson Printer (1290)
2nd port: Keyboard with Logitech MX-500 mouse (connected on the keyboard)
3rd port: Scanner (Epson 2480 Photo)
4th port: Macpower Prefect II 3.5 " External Storage Enclosure with a built-in Pioneer 115 DVD-burner.
Although all devices (of course, not the mouse
) have a separate power supply the DVD-burner behaves strange - almost if it does not get enough power. Burning works (with Toast 10) but most time it shows defect blocks on verify (nevertheless burned DVDs look ok and show no read errors on manual test but it's a bad feeling when it shows such errors on verify in Toast 10). The DVD-burner is ok because it works perfect when I put it in a PC (internal). So it must be something with the USB bus.
Can somebody explain the USB bus power specs of the 4 ports of the iMac 2009? I know that two ports share one power supply but I do not know which port is connected with which other? And how can this cause any problems if each connected device has its own power supply?
Thank you for any help!
I've the following configuration:
Firewire:
1st connected (via Firewire 800 cable; without separate power supply): Daisy Cutter DC-SATA 800+ enclosure with two Firewire 800 ports and a 300 GB Samsung Spinpoint SATA hd drive
2nd connected (via the second Firewire 800 port on the Daisy Cutter enclosure; separate power supply): Pleiades SATA 3.5 " hard drive enclosure (Super S Combo with all interfaces) with a 300 GB HD.
Does anybody know about the bus power requirements if two hard drives are plugged in? Shouldn't it provide 1500 mA in total (as the first one only needs 850 mA at max and the second has its own power supply I do not understand the problem here!)? As the first drive does not have a separate power supply (and does not need one as power comes from the Firewire port) and the second drive has a separate power supply it should be ok to supply enough power for both devices. It's interesting if I unmount the first drive BEFORE the second drive the second drive begins to behave strange (and system seems to be crashed until I turn off the drive). Same if the first drive is turned on but not mounted and I then turn on second drive - the second drive behaves like it does not get enough power (but it has a separate power supply). If both drives are mounted it seems ok. Can somebody explain the technical background of the Firebus and why it does behave this way on my iMac? And does anybody know why the second drive is not recognized at all if the first drive in the chain is not turned on?
Same problem with USB:
1st port (inner side): Epson Printer (1290)
2nd port: Keyboard with Logitech MX-500 mouse (connected on the keyboard)
3rd port: Scanner (Epson 2480 Photo)
4th port: Macpower Prefect II 3.5 " External Storage Enclosure with a built-in Pioneer 115 DVD-burner.
Although all devices (of course, not the mouse
) have a separate power supply the DVD-burner behaves strange - almost if it does not get enough power. Burning works (with Toast 10) but most time it shows defect blocks on verify (nevertheless burned DVDs look ok and show no read errors on manual test but it's a bad feeling when it shows such errors on verify in Toast 10). The DVD-burner is ok because it works perfect when I put it in a PC (internal). So it must be something with the USB bus.Can somebody explain the USB bus power specs of the 4 ports of the iMac 2009? I know that two ports share one power supply but I do not know which port is connected with which other? And how can this cause any problems if each connected device has its own power supply?
Thank you for any help!