PowerMac G5 No Boot

Discussion in 'PowerPC Macs' started by PowerMac G5, Sep 25, 2016.

  1. PowerMac G5 macrumors newbie

    PowerMac G5

    May 30, 2016
    Purchased a PowerMac G5 DP 2.5GHz PCIx Liquid Cooled a few weeks ago on an online classified site (it was only $10 so I might as well) the previous owner said that the mac would "boot when cold and wouldn't turn on when hot". Took it home, thinking it was an issue with the LCS I opened the machine up and gave it a large clean with an air compressor getting out all the dust I could, put it all back together and when I powered it on, no chime and no display on the monitor. All that happened was the fans turned on, then slowly ramped up until they were at full blast. I reseated the ram, reset the PMU, same thing. I read online that it might be a PRAM battery issue, so I ordered a new battery online replaced the old one. Still the same issue. I replaced the ram, same thing. And finally I took the LCS apart and reseated the CPUs.

    Is there anything I can do, I have also read that it is most likely a motherboard issue and that baking it in an oven "might" fix it.
  2. ITguy2016 Suspended

    May 25, 2016
    Motherboard issues with these systems are well known and probably the number one reason for non-operational G5's. Over the summer I picked up a dual 2.0GHz G5 system for $10, sold as non-operational. To my surprise it started up and I used it for about three hours the day I picked it up.

    However the next day it failed to start. Power button light came on, then flashed three times, and repeated. Researching the trouble code revealed incompatible memory which I thought odd because it worked the day before with the exact memory now being identified as incompatible. Further digging revealed the motherboard issue. There is a large chip on the opposite side of the motherboard (not visible when the motherboard is installed in the system) to the right of the memory slots and to the left of the processors. It is this chip where the solder joints fail thus leading to the non-operational system.

    The oven or heat gun tricks are attempts to reflow the faulty solder joints. From what I've read results have been mixed. I used a heat gun and the system became operational immediately after applying the heat. However after being off for a period of time (allowing the board to cool to room temperature) the system was no longer operational. Sadly I ended up cannibalizing parts from it and then giving the chassis with the remaining components away to someone on Craigs List.
  3. AmazingHenry macrumors 65816


    Jul 6, 2015
    Central Michigan
    If it doesn't turn on, at least you have a good table or seat. :D This sounds like a motherboard issue, but I'm not completely sure.
  4. mzs.112000 macrumors regular

    Apr 22, 2015
    He could use it as a fishtank.
    I've got an idea, buy a G5, seal up the case, take out the cooling system, dump in loads of vegetable oil, and use it as a deep fryer, due to the horrendous amounts of heat the G5 can put out.

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3 September 25, 2016