Past summer project - G5 Quad LCS rebuild

Discussion in 'PowerPC Macs' started by JRDN, Nov 24, 2015.

  1. JRDN macrumors member

    JRDN

    Joined:
    Oct 24, 2015
    #1
    Hey all, wanted to share the work I did on a Quad G5 I picked up earlier this year.

    Had a short obsession with owning the last generation of various PowerPC Macs.

    Found this Quad on ebay, no description and hardly any pictures. Asked the seller for a shot of the serial # label and found that it was a Quad! I took a risk and bought it for around $100

    It arrived in great condition. The case is in great shape, no bends, light cosmetic dings. stock 7800GT fan was noisy but it worked, came with a HD too!

    [​IMG]
    [​IMG]
    [​IMG]


    Come to find what others have in the past, the LCS needed a rebuild. Overtemp and checkstops, LOUD fans.

    This was my first watercooling venture, so shopping around for parts took some research to find what I needed.

    Using this guide I rebuilt the LCS using Tygon tubing, XSPC Clear fluid, DIYINHK DDC Pump PCB, New O-rings, and anti-kink coils.

    My unit originally had the dual pump system that was epoxied to hell. Deemed by me impossible to rebuild. So, I bought a LCS off ebay, single pump system and did a refurb. I did also buy a Panasonic unit too just for fun, but came to find that it doesn't fit at all. Hanging onto it for a future watercooling project.

    [​IMG]
    [​IMG]

    This LCS Loop went through about 4 revisions. Had to drain it about 6 times. Went through 3 different pumps because they were stuck max RPM. Finally replaced the PCB. Had to move the T-line reservoir to the intake side of the pump, added a kill coil, and adjusted tubing lengths a few times. I'm content now but I got seriously tired of taking this in and out of the G5.

    The pumps kept getting stuck on max RPM. Not sure what it is about taking this system apart but it managed to happen a few times. I had it wired up to the onboard connector but it had a really loud whine at full speed and wouldn't throttle down at all. Also, at full speed the pump was doing its share in heating the coolant, thus, raising core temps.

    My solution to the pump problem was to use a fan/pump controller. Regular cheap fan controllers don't have enough power to supply the pump with consistent voltage.

    I used the mCubed miniNG controller. This thing is really awesome. Gives enough startup voltage, has a sensor to make sure the rotor always spins (blockage recognition), choose between PWM or voltage based control. I chose voltage based and set it at one speed.

    [​IMG]

    Only catch, it doesn't communicate with the G5. Though I've found that on the lowest RPM it cools just fine. As long as coolant is flowing the core temps are around 35-40C idle.

    Unfortunately, there isn't a readout for changes made to the controller, speeds are adjusted with a potentiometer. Perfectly acceptable, and this pump is now inaudible and thermal calibration passed.

    Had issues with the thermal cal a bit ago. was throwing an "intake fan speed error" which I found there was a bent pin on CPU socket A. Put that back in place and boom, passed.

    [​IMG]

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    Configured with a flashed 7800GTX openmark score 18867
    added more RAM
    10.5.8
    using tricked versions of Dropbox and Skype. Even an older version of Photoshop too!

    [​IMG]

    This thing's great and hums along!
     
  2. rawweb macrumors 6502a

    rawweb

    Joined:
    Aug 7, 2015
    #2
    Excellent work JRDN! I feel your pain, I recently did a partial rebuild on my dual pump quad. It's a lot of work, but seeing the computer pass that thermal calibration brings smiles to anyones face.

    I'd love to see some temp tests from you. Idle and under load. Also test her with full crank (not reduced setting).

    I hacked Final Cut Studio 3 on my quad, but haven't yet been incredibly satisfied with the results. I think I've been too spoiled by the modern toys.
     
  3. flyrod macrumors 6502

    flyrod

    Joined:
    Jan 12, 2015
    #3
    Nice work! For stress testing CPUs, about the best I've seen is Power Fractal. Set the maximum count really high and watch the temperatures as it runs. It should top out in a few minutes.
     
  4. JRDN thread starter macrumors member

    JRDN

    Joined:
    Oct 24, 2015
    #4
    Did some testing just a bit ago. On the 'automatic' power setting with ambient temp around 18C. Clean install of 10.5.8


    Idle with pump speed manually set to where I can't hear it:
    [​IMG]

    To stress test I used the yes command and immediately the temps shot up close to 70C on one core before the system fans could react. The pump was adjusted to about 75% speed at this time and the fans slowly adjusted to the temps and settled around here:
    [​IMG] [​IMG]

    I increased the pump speed to 100% and the fan speeds dropped back to idle rpms and it held steady here:[​IMG]

    75% pump speed and letting the system fans compensate a bit seems to be the best mix at 100% load

    wanted to use the CpuTest app I saw, there's several options and I may play around with this later.
    With powerfractal do I need to install pooch? Lots of info on the main page, not quite a "just download and run" type of test. Does this also test the GPU at the same time?
     
  5. flyrod macrumors 6502

    flyrod

    Joined:
    Jan 12, 2015
    #5
    Pooch is if you want to run it on a bunch of networked computers. Power Fractal should run on its own. There are settings for altivec on/off and number of threads, but it should default on. It doesn't stress GPU.

    Thanks for posting your results!
     
  6. flyrod macrumors 6502

    flyrod

    Joined:
    Jan 12, 2015
    #6
    At lest on a G4, altivec processing seems to be the highest power draw (and thus CPU temperature). I just tried that yes > /dev/null method to peg a CPU. That leveled out at 55 degrees, then I started up Power Fractal, which went up to 60:

    [​IMG]


    I think dnetc might run a little higher, but it's more difficult than Power Fractal to set up if you just want to test a cooling setup.
     
  7. JRDN thread starter macrumors member

    JRDN

    Joined:
    Oct 24, 2015
    #7
    Just gave Power Fractal a go. I was running tests with it and realized I set my processors to "reduced" again. Was wondering why it was 50C on temps.

    flyrod, are your processors set to reduced?

    Anyway, I set processors to "highest" and avoided the "automatic" setting just to be sure.
    I set both "color speed" and "maximum count" to the highest settings. Took about 20 minutes to complete

    Here's firing up Power Fractal from idle. Pump speed 75% ambient 20C

    [​IMG]


    Got through a good portion of the test and here's where things settled. Pump speed 100%.
    [​IMG]

    I take back what I said about 75% pump speed and letting the fans compensate. I was getting mid 70s Celsius with that. Cranked the pump speed to max and it dropped 10 degrees instantly.


    AltiVec Power Fractal is also an app I got from the same page. Doesn't seem to have the same effect on temps. But it ran just the same.

    Testing with power fractal puts it right where the yes command put it except the fans are running faster
     

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