Ladies, gentlemen,

I have a MacAllyFirewire/USB 2.0 enclosure, model number PHR-100AC containing a 74.5 GB WD hard disk.

When I connect by USB everything works fine, but if I try to connect via Firewire it doesn't mount and Disk Utility doesn't see it.

I'm running a Dual 2 Ghz PowerPC G5, Mac OS X 10.4.11 with 4.5 GB DDR SDRAM.

This drive has mounted via Firewire on other Macs, just not this one.

Any ideas why this is so?

Thanks.

Hi Boyyo,

Wild guess - blown FireWire fuse/breaker on the G5? You can reset the ports by unplugging the Mac from the wall for fifteen seconds or more, then re-plug-and-pray that works...?

Happy Mac'ing!

Dan

Small edit...

Unplug EVERYTHING from your Mac and wait about fifteen MINUTES. Then, re-plug-and-pray.

Still no joy? Could be you need to reset the PMU (Power Management Unit), or replace your battery. You need a voltmeter to check the battery - if in doubt, simply replace it, sometimes these batteries can go flat in less than a year!

Open the side of your G5, remove the plastic deflector and look at the near-side of the logic board for a small, momentary switch just in front of the memory sockets. You will need to press this button ONLY ONCE in the following procedure:

QuoteTo reset the PMU on the Power Mac G5 follow these steps:

• 1. Disconnect the power cord and check the battery in the battery holder. The battery should read 3.3 to 3.7 volts. If the battery is bad, replace it, wait ten seconds, and then proceed to step 2. If the battery is good, go directly to step 2
• 2. Press the PMU reset button once and then proceed to the next step. Do not press the PMU reset button a second time because it could crash the PMU chip.
• 3. Wait ten seconds before connecting the power cord and powering on the computer.

NOTE: The steps above reset the computer's PRAM (parameter RAM). After resetting the PMU, be sure to set the time, date, and other system parameter settings.

That SHOULD get you going again if the firewire reset isn't the problem...

Happy Mac'ing!

Dan

p.s.: you'll need a LS1425OC 3.6V battery or exact equivalent, available through service at most Apple stores, or online at MacPro Online:

http://www.macproonline.com/

Hi Dan, I'll try all these things and see how it goes. Thanks.

Doesn't Command-Option-P-R also reset the PRAM?

Yes, but you want to reset the PMU, which incidentally also resets the PRAM. However, resetting the PRAM does not reset the PMU, so that alone will not do the trick.

Happy Mac'ing!

Dan

I have a very similiar thing a Macally PHR-250CC. One of the 2 Firewire 400 ports doesn't work. Fortunately the other one and USB are OK.