Just an aside, my trusty Mac Pro 2008 tower started behaving erratically a few weeks ago. Basically it wouldn’t power on, instead it would emit two faint relay type clicks a few seconds after pressing the power button. Leaving it unplugged overnight would occasionally result in it being boot-able the next morning.

Now I’ve been through a few spare parts on this particular computer – in particular graphics cards (it’s on its third). The overnight powerdown fix pointed me towards SMC problems, but replacing the motherboard battery didn’t resolve anything. Which lead me to the PSU. I tried using compressed air to blow the dust out of it in case it was some kind of thermal issue to no avail.

Shortly after that it stopped booting entirely – still giving me only the clicks. Power supply it is. Being Apple of course – it’s not just an ATX supply but an entirely custom job made by Delta.

I tried one of the local Mac breaking yards in Akiharbara, But although they would sell me a working used ‘Pro 2008 for $500 they were unwilling to come to an arrangement for the still beating heart of one of them. Given I have far too much junk already, adding the husk of a Mac Pro to the pile didn’t feel like a good move.

So I settled on buying a new PSU from MacPartsOnline.com after reviewing the reseller ratings of various other vendors. Several hundred dollars (and a few days) later the new power supply arrived very nicely packed in specially cut foam.

The replacement process was awkward but not difficult. It’s summarized better elsewhere but basically:

• Remove the side of the case
• Pull out all the HDDs
• Remove the CD-ROM box (unplugging the PATA and power cables)
• Remove the cable hiding box at the back of the case
• You may need to remove all PCI-e cards to get to the Torx screws…
• Undo the four badly located Torx screws that are visible by looking up underneath the power supply
• Remove the fan
• Unplug the flat power cables that link the case with the PSU
• Pull the power supply out
• Reverse procedure to install

Once done my Mac was online immediately – overall took about two hours. On investigating the faulty power supply I found nothing special or obviously wrong with it; no bulging capacitors, burned out chips or transistors.

One interesting thing is large number of adjustment pots, which suggest that it may have just drifted out of alignment over time. However the probability of working out the appropriate adjustment without a service manual was pretty small.

Anyway – I hope I can get a few more years service out of the box, thanks to the reduction in year-on-year improvement to single-threaded CPU performance 2008 X5482 Xeon’s have 60% of the performance of a brand new Xeon E3-1270.

The new comparable Mac Pro is the best part of $5,000 USD, and wouldn’t be noticeably faster for 90% of what I use it for, since I already upgraded with a fast SSD (highly recommended by the way).

I hope this is of use if you run into Mac Pro 2008 issues.