Strange red light by power switch

Discussion in 'PowerPC Macs' started by diver pete, Aug 13, 2012.

  1. diver pete macrumors newbie

    Aug 13, 2012
    Hi there,
    I am working on a Powermac G5 tower at the moment. It had blown a few components inside the power supply which I have replaced. At startup everything was fine and I have achieved a 'chime' and installed an operating system.
    However, when the power cord is put into the machine, I get a click and a red light appears on LED 7. When I push the power button, the light goes out and the machine starts normally and runs fine. At shutdown, the red light comes back on.
    Does anyone know what this light signifies and whether I should be concerned about it or not?
    Thanks in advance for your help.
  2. jbarley macrumors 68040


    Jul 1, 2006
    Vancouver Island
    check out this link on power mac diagnostic LED's
    Might be of some help.
  3. 666sheep macrumors 68040


    Dec 7, 2009
    OP, google "Power Mac G5 Late 2005 service manual". You should find it on Scribd or elsewhere. It contains much better info than Apple support site.
    LED 7 is known as "checkstop". It could indicate RAM or CPU problem.
  4. Nameci macrumors 68000


    Oct 29, 2010
    The Philippines...
  5. diver pete thread starter macrumors newbie

    Aug 13, 2012
    Thanks for your help guys.
    The service manual was really useful, especially the section on diagnosis. The machine seems to be running ok so I guess the indicator LED is showing a trickle charge present before the power button is pressed. I think I will run it for a week or two and see how it goes.
    I also noticed in the manual that LED 3 should illuminate when the plastic cover is removed as well as an amber on LED 4. I am missing the indication on LED 3 at the moment and that could be a concern as it confirms the correct voltage is supplied.
    I think the next step will be to check all the voltages out of the power supply unit.
    Thanks again,

Share This Page