iMac FireWire not working (tried everything?)

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Level 1

17 points

iMac FireWire not working (tried everything?)

My firewire port wasn't working with my video camera a couple months ago, and I just wrote it off to 'compatibility' issues.

I've since tested it with different devices and different cables and can still get no joy.

I've reset everything suggested on here, and nothing. I've put the iMac in target disk mode and hooked it into another computer, and nothing. Today I even tried going into the FW800 port, and still nothing.

I have a bus powered audio interface that doesn't boot up fully when going into the FW400 port. It boots up fully into the FW800 port, but still isn't recognized (nor is anything else).

I've checked in System Profiler and the FireWire shows up there, listing it as :
FireWire Bus:
Maximum Speed: Up to 800Mb/sec

It's really frustrating not to be able to use any of my peripherals.

The computer is a couple of years old so I no longer have a warranty on it, and the Apple store isn't exactly the cheapest repair place in the world.

If the above symptoms seem like some kind of hardware problem (a bad FW Card internally), I feel handy enough with computers to replace it on my own if I can narrow it down to that.

Thanks

iMac 2GHz Core 2 Duo, Mac OS X (10.6.2)

Posted on Dec 11, 2009 7:55 AM

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Answer 1

MGW

Level 7

27,041 points

Dec 11, 2009 8:46 AM in response to kriista

Have you tried resetting the firewire bus? See [this|http://docs.info.apple.com/article.html?artnum=88338] Apple article.

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Answer 2

kriista Author

Level 1

17 points

Dec 11, 2009 1:29 PM in response to MGW

Yeah I tried that. I also reset the MCU and PRAM (or similar acronyms).

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Answer 3

Dec 11, 2009 1:48 PM in response to kriista

The FireWire hardware internally is directly on the logic board, I believe.

To rule out a possible software-related issue, you should try starting up from your Mac OS X installation disc; insert disc and restart with the C key held down. This will get you to Installer's screen (after you select language). Go up to the menu bar and select to run Disk Utility, under Utilities.

Connect a FireWire storage device. Does it appear in the Disk Utility sidebar?

If it does, then the port is probably working fine and there is some issue with the current system installation. If it does not, then it is more likely that the problem is hardware-related. FireWire ports can fail; I had it happen to the front port of a Power Mac G5 (fixed while under AppleCare).

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Answer 4

kriista Author

Level 1

17 points

Dec 12, 2009 5:44 AM in response to Kenichi Watanabe

I only had a 10.4 OSX CD laying around (don't know what I did with my 10.6 disc), and tried this and it didn't say anything about firewire. I even tried booting up my laptop in target disk mode and connecting it to the disc run OSX utilities and it didn't show up.

Going to try it again with a 10.6 disk tomorrow to see if that makes any difference. Or would it?

System profiler run from the install disk still found the FW port and said it was groovy at 800Mbs though.

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Answer 5

Dec 12, 2009 1:39 PM in response to kriista

The FireWire port and FireWire bus are not necessarily the same things. The bus can be active and recognized, but the port may be faulty in some way.

As long as your iMac is one that supports booting with Tiger, using a Tiger installation disc should be as valid a test as using a Snow Leopard disc.

Since you have another Mac (the laptop), you can try the opposite test using FireWire Target Disk Mode. Start the iMac in target mode and connect it to the other Mac. That will also take the currently installed system out of the picture, since the target mode function is in the iMac's ROM.

Just be sure you are trying different FireWire cables in these tests.

I also reset the MCU and PRAM (or similar acronyms).

I don't know what "MCU" is, but if it was not resetting the SMC, you should go through this procedure

http://support.apple.com/kb/HT3964

which is basically unplugging the iMac completely and reconnecting using a precise procedure. Apple changed the procedure document recently, so take a look to make sure you did what it says before.

If those things do not work, it is more likely that there is a hardware problem.

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Answer 6

kriista Author

Level 1

17 points

Dec 12, 2009 3:07 PM in response to Kenichi Watanabe

So I meant SMC. So many acronyms.

I just redid what that article said to be safe and nothing.

I've tried target disk mode both ways (putting my laptop in TDM, and it wouldn't show up on the iMac, and vice versa).

I've also tested every device I have (video camera and sound card, with multiple cables, and through both the FW800 and FW400 ports (via an 800to400 adaptor).

I also find it weird that my FW400 port isn't putting out enough bus power to turn on my FW sound card, but the FW800 port is (though it's not recognised either way).

When you say the FW Port and Bus are different, does that mean the FW port(s) as in they are one thing internally?

When I boot from the install disc, and run disk utility. What exactly am I looking for? It should literally say "Connect a FireWire Storage Device" in the sidebar (to the left) where it lists My HD and the loaded OSX CD?

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Answer 7

kriista Author

Level 1

17 points

Dec 14, 2009 5:28 AM in response to kriista

OK, tried with a Snow Leopard CD and still nothing about firewire anywhere in the utility program, much less the sidebar.

Does this point to a faulty logic board now?

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Answer 8

Dec 14, 2009 12:57 PM in response to kriista

That's what it meant for me.

Had trouble connecting my video camera to my iMac. Replaced cable - didn't work, tried the resets - didn't work. The camera worked on the macs at the apple store, so that wasn't the trouble.

Took my iMac to the Genius Bar. Due to the backlog of i7 orders, my options were to either replace the computer with an i5 or have the logic board replaced - 5 day turnaround. Which system do you have? Did you take it to Apple?

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Answer 9

Dec 14, 2009 1:24 PM in response to kriista

When you say the FW Port and Bus are different, does that mean the FW port(s) as in they are one thing internally?

Mac OS X may still see the bus (the portion that controls the interaction between the Mac and device), but the ports that are on the bus may not be working properly.

When I boot from the install disc, and run disk utility. What exactly am I looking for? It should literally say "Connect a FireWire Storage Device" in the sidebar

In Disk Utility, it will only show something in the sidebar if you have a FireWire storage device connected; it would show the name/type of the device and the volume on the device.

Unfortunately, FireWire ports can go bad. They seem more susceptible, compared to USB ports. I had it happen to the front port on a Power Mac G5 (fixed under AppleCare).

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Answer 10

kriista Author

Level 1

17 points

Dec 14, 2009 4:27 PM in response to Kenichi Watanabe

Oooh. I understand now.

I'm meant to hook up a FW drive (in my case, a laptop in target disk mode), then boot off the disk on the iMac to see if the FW HD shows up in disk utility?

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Answer 11

Dec 14, 2009 4:37 PM in response to kriista

A Mac in target disk mode would work as the storage device. If the port is working, that Mac's hard drive should appear in the Disk Utility sidebar.

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Answer 12

kriista Author

Level 1

17 points

Dec 14, 2009 6:25 PM in response to Kenichi Watanabe

OK, officially have a hardware problem then.

Is there anything else on the logic board to test to see if the whole thing is faulty, or however this works.

I've tested both FW400 and FW800 ports so it's not just the actual port, unless they are the same internally.

And is the logic board a user serviceable part? (I'm out of warranty and can't afford apple store repair prices).

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