iMac Firewire 800 port not supplying power

Question

kaicuts Author

Level 1

5 points

iMac Firewire 800 port not supplying power

Hi,

The FW800 port on my iMac suddenly stopped supplying power to bus-powered drives.

The same drives work/mount when I use an AC adapter.

Have thoroughly trouble-shot (shooted?) the hard drives/cables on a different computer.

Tried the SMC reset (unplug for 15-seconds).

Anything else I can try before sending it to Apple?

System Details:

iMac

27-inch, Mid 2011

Processor 3.4 GHz Intel Core i7

Memory 16 GB 1333 MHz DDR3

Graphics AMD Radeon HD 6970M 2048 MB

Software Mac OS X Lion 10.7.5 (11G63)

iMac, Mac OS X (10.7.5)

Posted on Mar 31, 2015 5:24 PM

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Answer 1

SeaPapp

Level 7

26,486 points

Mar 31, 2015 7:33 PM in response to kaicuts

Other than to unplug all firewire devices and shut the computer down for a few minutes I don't know of any way to reset firewire.

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Answer 2

den.thed

Level 9

77,158 points

Mar 31, 2015 8:38 PM in response to kaicuts

Try the SMC reset again, only this time disconnect everything and wait at least 60 seconds instead of 15 seconds.

If that does not help, try > https://support.apple.com/en-us/HT204063

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Answer 3

kaicuts Author

Level 1

5 points

Mar 31, 2015 9:33 PM in response to den.thed

I originally waited 5 minutes, but tried 15 minutes this time. No dice.

Also originally reset the Parameter Ram, which is now called NVRAM…learned something new today.

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Answer 4

den.thed

Level 9

77,158 points

Apr 1, 2015 7:01 AM in response to kaicuts

Not sure how many or what FireWire drives you have, but that iMac's FireWire 800 port only supplies 7 watts of power. If the total load of your drives is more than 6 or 7 watts, you should be using a power adapter on at least the first drive in the FireWire chain.

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Answer 5

kaicuts Author

Level 1

5 points

Apr 1, 2015 4:45 PM in response to den.thed

I only use one bus powered drive at a time.

Have been using them without issue since I got the iMac in 2011. The drives currently work fine on my MacBook Pro.

Here are the drives I use: http://eshop.macsales.com/shop/firewire/on-the-go

Bus powered RAID (2 drives): http://eshop.macsales.com/shop/firewire/EliteALmini/RAID/eSATA_FW800_FW400_USB

Genius Bar it is….

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