Dead PMG5 (June 04, LCS dual-2.5)

Discussion in 'PowerPC Macs' started by computiNATEor, Mar 24, 2018.

  1. computiNATEor macrumors newbie

    computiNATEor

    Joined:
    Nov 5, 2015
    Location:
    Orange County, CA
    #1
    Hey there,

    I need some advice regarding my next course of action with my June 04 PowerMac7,3 (dual-2.5 w/ Liquid Cooling System).

    I recently replaced all the hoses and the coolant, and reapplied thermal paste after a thorough cleaning. I blew the case out with some compressed air, too.

    I haven't used this machine at all in at least a year, and before I started it up, I saw some signs of liquid cooling system leaks, so I wanted to freshen it up a bit. I replaced all of the cooling hoses with 3/8ths automotive fuel line, and replaced the o-rings with Viton rubber o-rings (#026).

    Currently, when I press the power button on the front panel, I get nothing. No power LED (the one above the power button), no fans, no clicks, nothing. I've tried a couple things; namely, a different power cable (known working), hitting the PMU reset button (nothing), and a couple (unknown charge) PRAM batteries (still nothing).

    When I replaced one of the PRAM batteries and reattached the power cord, I got a "click" sound, and a white LED near the front of the logic board flashed briefly.

    My first guess will be to replace the PRAM battery with a new one and see if that helps, but assuming that it doesn't, what should be my next course of action? Power supply? The button itself?

    Thanks for your help,

    Nate
     
  2. computiNATEor thread starter macrumors newbie

    computiNATEor

    Joined:
    Nov 5, 2015
    Location:
    Orange County, CA
    #2
    When I plug the power cord in after hitting the PMU reset button, I hear a click and see the front panel/power light flash, but nothing else. Still unresponsive. I tried jumping the pins described in this video, too, but that also had no effect.


    I suspect the power supply may be faulty. I'll try swapping it with some spares I have early next week.
     
  3. pl1984 macrumors 68000

    Joined:
    Oct 31, 2017
    #3
    Where was the location of the liquid cooling leaks? Can you provide pictures of the leakage and location? It may be the liquid seeped into the power supply.
     
  4. computiNATEor thread starter macrumors newbie

    computiNATEor

    Joined:
    Nov 5, 2015
    Location:
    Orange County, CA
    #4
    Good point. They leaked at the o-rings, but as I haven't used this system in at least a year, the liquid may have evaporated before I noticed.

    I did notice the residue on top of the power supply:
    IMG_2367.jpg
    IMG_2366.jpg

    And with the processor cards removed:
    IMG_2372.jpg
     
  5. pl1984 macrumors 68000

    Joined:
    Oct 31, 2017
    #5
    It doesn't appear to be extensive wrt the power supply, more like surface contamination. I recommend cleaning up the processor heat sink connections and moving forward with the power supply replacement.
     
  6. computiNATEor thread starter macrumors newbie

    computiNATEor

    Joined:
    Nov 5, 2015
    Location:
    Orange County, CA
    #6
    Yep, I've done that. Over the last week I fully disassembled the LCS, installed new Viton o-rings, cleaned off the surface corrosion with a brass wire brush and some alcohol, replaced the very brittle and seeping coolant hoses with 3/8ths fuel line, and refilled the cooling system with coolant.
     
  7. computiNATEor thread starter macrumors newbie

    computiNATEor

    Joined:
    Nov 5, 2015
    Location:
    Orange County, CA
    #7
    Update: I pulled everything out of the case; I think I didn't get the processors fully seated or something. The power supply registered proper voltages when I checked it with my multimeter. I had it relearn the thermal calibration, and it's running faster than ever.
     

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