View Full Version : Firewire problem on G4 MDD

12-11-2008, 02:37 PM
Looking for some direction on how to tackle this problem.

I have a MDD G4. a Dual bumped up to 1.42 about 3 years ago.

Computer itself runs rock solid.

My problem are the two firewire ports on the motherboard.

If I attach a firewire drive the computer immediately powers off. When this happens Pushing the power button on the front of the computer does nothing.
I have to physically unplug the computer. Then it powers up normally.

Thing is if I power off the computer, hook up a firewire drive to either port and then power up -- everything is fine. Computer powers up. Drives function etc.

So it appears the firewire ports themselves aren't blown.

A friend suggested I might have a bad power supply.

Before I start spending money I want to make sure this is a likely candidate and was hoping somebody here might have some thoughts on the matter.

While I'm on the subject...

I bought a Firewire/USB2 card to put in one of the slots a few months ago.
WOrked well enough for a few days but then I started getting the occasinal blue screen and unexpected freezes after the computer went to sleep.

So I pulled it.

I'm told there are certain brands that work on the MDD and some that don't.

Any recommendations? I forget what type I bought.

Thanks for any help you can provide.

12-11-2008, 04:01 PM
Your PCI card will work fine if you turn off sleep. Most everyone I know, and certainly every computer here at MacGurus, never sleeps a computer or hard drive for any reason. Sleep equals problems, especially with Firewire cards. Just turn it off. Your drives and other hardware will last longer, maintenance will get done. Mac OSX does automatic maintenance at 3AM.... if you are up and running and not sleeping. If your computer never gets left up you either must do the maintenance manually or expect to have long term stability issues.

On your motherboard FW bus, you might try a Open Firmware reset. Hold the Command+Option+O+F keys during startup. At the '>' prompt type:

Hit Return
Hit Return
Hit Return and your computer will restart. See if that clears it up.


12-11-2008, 04:23 PM
Thanks for the advice and the information on resetting the firmware. I'll give it a try and report back.

12-11-2008, 04:49 PM
Okay I reset the firmware and rebooted.

Thought it did the trick at first. I plugged in one firewire drive and no sudden crash/powerdown. Firewire drive powered up and the drive spun.

However it never mounted. I unplugged that one and plugged in a different fire wire drive and I got the usual crash/powerdown.

As usual the power button on the front of the computer didn't do anything when I pushed it. Had to unplug the power cord and plug it back in. Then the power button worked. **

I hooked up both drives and rebooted. Both mounted and work fine.

** one thing I noticed when I was unplugging/plugging in the power cord on the back of the computer. With the computer powered down there was a humming/static noise coming from the area of the power supply. Is this normal?

Thanks again.

12-11-2008, 04:52 PM
incidentally if I take your advice about turning off deep sleep and a firewire/usb2 card will function on my MDD I can live without the ports on the back.

I thought perhaps it was systematic of a power supply about to go or something. Wasn't sure.

On the subject of a firwire/usb2 combo do you have any recommendations?
Or maybe which ones to avoid. Or are they all pretty much the same.

12-11-2008, 05:18 PM
Next reset to try is a PMU reset. That is a leeetle button on the motherboard near the battery. Shutdown, disconnect power cable, press and hold the PMU reset button for 5 seconds. Restart. You will have to reset clock and startup disk. The PMU is the Power Management Unit. It controls the power button, power supply and on off functions.

Most all PCI FW/USB cards are relatively equal. They all don't support sleep. There are only 2 or 3 different chipsets. Whatever should be fine.

No telling on the noise from the PS. Some of them make a bit. If it comes down to it a replacement can be had from www.galaxyhp.com Good folks, David runs the place and is really good diagnostician via email or phone. They are in Oregon on west coast time.