Hello All, I recently acquired a Power Mac G5 Quad, the last and fastest of the PPC Macs. It was missing its hard drives and was sported a failing video card. I replaced the video card with an nVidia Quadro FX 4500 and added two hard drives that I had in stock. I turned the Quad on, only to discover that the fans quickly ramped up to 3300 RPM in order to hold CPU temperatures in check (...which they did! CPU temps were in the mid 40s C, which is perfect). However, the noise from the fans running at such high RPMs made the machine effectively unusable. I burned Apple Service Diagnostics 2.6.3 to a DVD and ran Thermal Calibration on the Quad. Both CPUs failed. Clearly it is time to service the Liquid Cooling System (LCS), the most feared and complex maintenance task that I am aware of in all of the Mac world.
That is where this thread starts. This thread will chronicle the journey from a hopelessly noisy, barely cooled G5 Quad to a hopefully quiet and peaceful G5 Quad that can be productively used. This is a long, complex and challenging maintenance task - I expect that it will takes weeks, if not months, to complete.
I invite you to come along with me for the ride. Please feel free to contribute your thoughts, possible steps and any other wisdom you may wish to impart, as you see fit. As I am going along, I am going to document all of my work, and when done, produce a concise guide to servicing Quad LCS units which I will post here and at my retro-computing blog, www.retro-computing.com.
So, where do we start? Well, the machine went "on the bench" this afternoon, as you will see from the attached photo. My first step was the Thermal Calibration. Now that this has definitively failed, the next steps will be to do a thorough interior cleaning and then extract the CPUs. I will repaste them, put them back and see if that helps. If it does not, and "not" is the expected outcome, I will proceed to the much more difficult job of draining and recharging the LCS, a task about which volumes have been written by other authors in various places.
I will post more in this thread as the work progresses. Stay tuned!
BTW, Thermal Calibration did in fact fail, but it was not without value and impact. Thermal Calibration rewrites the data in the calibration ROMs to match current circumstances, and this had the effect of lowering the idling fan revs on my new Quad from 3300 RPM to about 2200 RPM. This is still rather more noisy than I want to deal with, and so the LCS work is definitely "on", but it is an improvement. If you have a Quad whose fans are running just a small amount too fast, Thermal Calibration may just bring fan revs back to a more peaceful level. Remember however, as the Apple diagnostics guide says, you cannot calibrate your way out of a failing LCS; you may be able to buy some time, but eventually, the unit has to be serviced.
That is where this thread starts. This thread will chronicle the journey from a hopelessly noisy, barely cooled G5 Quad to a hopefully quiet and peaceful G5 Quad that can be productively used. This is a long, complex and challenging maintenance task - I expect that it will takes weeks, if not months, to complete.
I invite you to come along with me for the ride. Please feel free to contribute your thoughts, possible steps and any other wisdom you may wish to impart, as you see fit. As I am going along, I am going to document all of my work, and when done, produce a concise guide to servicing Quad LCS units which I will post here and at my retro-computing blog, www.retro-computing.com.
So, where do we start? Well, the machine went "on the bench" this afternoon, as you will see from the attached photo. My first step was the Thermal Calibration. Now that this has definitively failed, the next steps will be to do a thorough interior cleaning and then extract the CPUs. I will repaste them, put them back and see if that helps. If it does not, and "not" is the expected outcome, I will proceed to the much more difficult job of draining and recharging the LCS, a task about which volumes have been written by other authors in various places.
I will post more in this thread as the work progresses. Stay tuned!
BTW, Thermal Calibration did in fact fail, but it was not without value and impact. Thermal Calibration rewrites the data in the calibration ROMs to match current circumstances, and this had the effect of lowering the idling fan revs on my new Quad from 3300 RPM to about 2200 RPM. This is still rather more noisy than I want to deal with, and so the LCS work is definitely "on", but it is an improvement. If you have a Quad whose fans are running just a small amount too fast, Thermal Calibration may just bring fan revs back to a more peaceful level. Remember however, as the Apple diagnostics guide says, you cannot calibrate your way out of a failing LCS; you may be able to buy some time, but eventually, the unit has to be serviced.