This week’s repair is on a dual-processor Power Mac G5. In its day, this particular model was Apple’s flagship desktop with dual 2.5GHz processors, up to 8GB of RAM and an optional video card that would drive a 30-inch Cinema Display. Part of the reason the G5 processor never made it past 2.7GHz was its heat output. Earlier Power Mac G5s relied on giant heatsinks and robust fans to cool themselves, but at the 2.5GHz level a more substantial liquid cooling system was used.
Earlier Power Mac G5s used two separate processor modules that could be replaced individually, but this model’s liquid cooling system incorporated both processors, a coolant pump, and an actual radiator not unlike that found in your car. Coupled with the powerful fans, this liquid cooling system was quite effective at keeping processor temperatures reasonable.
Unfortunately for this customer, a local school district using the machine as a PowerSchool server, the liquid cooling system began to leak. The machine presented with intermittent kernel panics and random shutdowns, and having seen similar symptoms from other liquid cooled G5s, I suspected a leak straight away.
After removing the aluminum side panel and clear lexan air deflector, I noticed coolant residue on the main logic board and a small, barely moist puddle under the processor module. Knowing that the repair cost would far exceed the real-world value of the machine, I used Apple’s support-for-certified-techs system to request coverage even though the machine was years out of warranty. They said yes, and the next day a replacement processor, logic board, and power supply were delivered.
Jon installed these components, but the machine wouldn’t power on. Re-tracing his steps and relying on intuition, he declared the parts dead on arrival. A new batch arrived the next day, and this time around the liquid cooling system was leaking into its shipping container! One more try brought another leaking processor.
At this point, our customer called Apple directly, explained the situation, and asked how she could most quickly get back up and running. The Apple rep happily offered a shiny, brand new, eight-core Mac Pro. Two days later, the Mac Pro was safely in our server room (we offer co-location services) hosting the PowerSchool system for our local school district.