Red Light Flash

Discussion in 'Mac Pro' started by 3runjosh, May 24, 2009.

  1. 3runjosh macrumors member

    Dec 7, 2008
    Hi, I was starting up my Mac Pro this evening in a dark room and noticed a flash of red light for half a second upon pressing the power button. Being curious of this I shut down the computer took off the side panel and tried powering it up again. I saw 4 lights on Memory Riser B flash on for half a second then disappear. In System Profiler it shows all my ram is 'OK' but I have never witnessed this flash of red light before. Is this a normal thing to occur when powering up a Mac Pro late 08 model or should I contact Apple over this?
  2. surflordca macrumors 6502a


    Nov 16, 2007
    Ontario, Canada
    I would think it is normal as mine does it also. I think it is just getting power before the computer reads the memory.
  3. djjclark macrumors regular

    Feb 17, 2008
    They are hardware error indicators. They default on when power is applied and are turned off once the memory controller/memory is validated. It is normal to see them flash on power up.

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