Donald Mckelvey

Q: G5 startup light flashes 3 times then after a pause flashes 3 times etc.

I have a Power Mac G5 1.6 GHz which froze today. I had to shut it down by pressing and holding the startup button. Now when I try to restart it by pushing the startup button the light on the startup button flashes 3 times then after a short pause it flashes 3 times again and this repeats over and over. The chimes don't play and the screen doesn't light up. I tried pushing the Cuda/ PMU but that didn't help. Any suggestions?

Mac Mini (2nd Gen), Mac Pro (2 X 2.66 GHz), Mac OS X (10.6.1)

Posted on Aug 12, 2010 8:36 AM

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Q: G5 startup light flashes 3 times then after a pause flashes 3 times etc.

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  • by Niel,Helpful

    Niel Niel Aug 12, 2010 10:23 AM in response to Donald Mckelvey
    Level 10 (313,513 points)
    Mac OS X
    Aug 12, 2010 10:23 AM in response to Donald Mckelvey
    Remove and reinsert all of the computer's RAM.

    (53296)
  • by BDAqua,Helpful

    BDAqua BDAqua Aug 12, 2010 12:23 PM in response to Donald Mckelvey
    Level 10 (123,765 points)
    Aug 12, 2010 12:23 PM in response to Donald Mckelvey
    Hi Donald,

    Can you count the beeps or flashes?

    1 beep = no RAM installed
    2 beeps = incompatible RAM types
    3 beeps = no good banks
    4 beeps = no good boot images in the boot ROM (and/or bad sys config block)
    5 beeps = processor is not usable

    In addition to the beeps, on some computers the power LED will flash a corresponding number of times plus one. The LED will repeat the sequence after approximately a 5-second pause. The tones are only played once.

    Note: In this case, a flash is considered to be 1/4 second or 250 ms or greater in length.
  • by old comm guy,

    old comm guy old comm guy Aug 12, 2010 1:45 PM in response to Donald Mckelvey
    Level 4 (2,244 points)
    Aug 12, 2010 1:45 PM in response to Donald Mckelvey
    With regards to your particular machine, the following holds on flashes:

    • 2 Flashes: No RAM is installed or detected.
    • 3 Flashes: Incompatible RAM types are installed.
    • 4 Flashes: No RAM banks passed memory testing.
    • 5 Flashes: No good boot images are detected in the boot ROM (and/or there is a bad
    sys config block).
    • 6 Flashes: The processor is not usable.

    One stick is possibly corrupted or just, as an earlier post, needs to be reseated. If reseating does not do the trick, then you have to start removing pairs until you eliminate the bad stick.
  • by Donald Mckelvey,

    Donald Mckelvey Donald Mckelvey Aug 12, 2010 2:58 PM in response to Donald Mckelvey
    Level 1 (25 points)
    Aug 12, 2010 2:58 PM in response to Donald Mckelvey
    I made an error in reporting the processor speed. It is 1.8 GHz, not 1.6 GHz. The model is M9031LL/A , with PCI-X. Since I couldn't start the G5 I had to look up my order on another Mac.

    The startup light gives 3 quick flashes and then dims for about 3 seconds and then 3 quick flashes and repeats this.

    I removed two RAM strips that I had added about 6 months ago. This didn't help. Then I removed the two original RAM strips and replaced them with the other two. This didn't help. Then I took out the two newer RAM strips and put the original RAM strips back in, leaving the two newer strips out. Still no go.
  • by BDAqua,Solvedanswer

    BDAqua BDAqua Aug 12, 2010 3:22 PM in response to Donald Mckelvey
    Level 10 (123,765 points)
    Aug 12, 2010 3:22 PM in response to Donald Mckelvey
    Strange as it sounds, try heating the area around the RAM slots with a Hair Dryer for 3-5 minutes, see if it boots then.
  • by old comm guy,

    old comm guy old comm guy Aug 12, 2010 5:15 PM in response to Donald Mckelvey
    Level 4 (2,244 points)
    Aug 12, 2010 5:15 PM in response to Donald Mckelvey
    Donald Mckelvey wrote:

    The startup light gives 3 quick flashes and then dims for about 3 seconds and then 3 quick flashes and repeats this.


    Just for grins, remove all RAM and try to power up and see if you get the two-flash response. If not, then there is a real puzzle here, as something strange is going on. If you do get two flashes, then that is helpful in that it indicates that the RAM detection firmware seems to be somewhat working anyway.

    BDAqua is also on a good track, as we have been seeing some socket problems in these machines as well.
  • by mplaster,

    mplaster mplaster Aug 12, 2010 8:46 PM in response to BDAqua
    Level 1 (0 points)
    Aug 12, 2010 8:46 PM in response to BDAqua
    Wow. I have been having the EXACT same problems as the threadstarter. About 2 weeks ago it froze, and from tips i read here in the forums, tried switching around my RAM sticks. For a while it worked. Then i broke off one of the end snap-in bracket holders. So now i lost an entire row (two, technically) of available RAM. Anyhow, it still would perform random starts each time i switched RAMs around. Then 4 days ago it just plain would NOT start up at all. The stupid little three flashes taunting me.

    So i ran up to the local Target, bought me a hair dryer. Toasted up the area around the RAM brackets and whaddya know!!! It WORKED! What planet am i on when a nine dollar Conair Salon Series can repair a $3,000 PowerMac. I dunno, but i'll take it!

    My only follow up question would be: Is this just a cheesy temporary fix? Should i expect it to NOT boot after my next shutdown? Should i plan to have my hair-dryer in my studio now and expect to need to warm it up every time now? (In other words, can i return the hair-dryer or should i hang on to it? )

    Thanks again... you guys are geniuses!!!
  • by japamac,

    japamac japamac Aug 12, 2010 9:19 PM in response to mplaster
    Level 7 (24,390 points)
    Aug 12, 2010 9:19 PM in response to mplaster
    Is this just a cheesy temporary fix?

    Cheesy or not, a board re-flow is the only other option.
    Should i plan to have my hair-dryer in my studio now and expect to need to warm it up every time now? (In other words, can i return the hair-dryer or should i hang on to it? )

    Keep the hair dryer, or better yet, leave the G5 running.
    The continual heating and cooling of the memory slot/logic board connections is what is breaking the solder connections.
    Keeping the machine hot is better.
  • by BDAqua,

    BDAqua BDAqua Aug 12, 2010 9:35 PM in response to mplaster
    Level 10 (123,765 points)
    Aug 12, 2010 9:35 PM in response to mplaster
    Thanks mplaster, as jmac says just keep it running, Sleep may or may not work, but your G5's days are limited.
  • by Donald Mckelvey,

    Donald Mckelvey Donald Mckelvey Aug 14, 2010 6:44 AM in response to Donald Mckelvey
    Level 1 (25 points)
    Aug 14, 2010 6:44 AM in response to Donald Mckelvey
    I want to thank everyone for their help. I tried the hair dryer but I only gave it two minutes and it didn't work. I'm away from home now so I will give it a more thorough trail when I get home. My solution to this problem has been to order a refurbished iMac from the Apple store. For $1267 I'm getting a 3.06GHz processor, 1TB drive, 4 GB ram and 27 inch screen. I hope the hair driver doesn't work! I should mention that this is my wife's computer. I'm still using the Mac Pro listed in my profile.
  • by Ultrabeaker,

    Ultrabeaker Ultrabeaker Aug 15, 2010 12:09 PM in response to Donald Mckelvey
    Level 1 (0 points)
    Aug 15, 2010 12:09 PM in response to Donald Mckelvey
    I am in the same boat. Dual 1.8 G5 which has been a dream until today. Won't boot and I get the same 3 blinks of the light, then dim. Repeat. I have remove and reset all of the ram and re-loaded it and nothing. I am about to get the hair dryer. If this does not work, what is the next step? Is it repairable? does this generally mean that the sockets are bad, and they CAN be replaced or are we looking at something new that needs to be done?

    I know I'm asking you all to diagnose something, but I need to be informed in dealing with my explanation to my wife as to why I spend more money. Unfortunately the local store I deal with, Mac Haven, whom I trust, charges $125 just to diagnose it. So, is it time for a new Mac?
  • by BDAqua,

    BDAqua BDAqua Aug 15, 2010 12:25 PM in response to Ultrabeaker
    Level 10 (123,765 points)
    Aug 15, 2010 12:25 PM in response to Ultrabeaker
    Hi Ultrabeaker, and a warm welcome to the forums!

    If this does not work, what is the next step?


    A very few have been able to skip the 1st pair, (inner pair), of sockets & get it to work.

    Is it repairable?


    There's one place in Germany that has had success repairing/reflowing them.

    does this generally mean that the sockets are bad, and they CAN be replaced or are we looking at something new that needs to be done?


    It generally means that the new at that time Lead free Solder has lost connections inside the 5 layer Logic board around the RAM slots due to expansion & contraction.

    So, is it time for a new Mac?


    Likely so, the bottom Mac these days can beat our top of the Line Macs from yesteryear.
  • by moraine music,

    moraine music moraine music Aug 16, 2010 1:52 PM in response to Donald Mckelvey
    Level 1 (0 points)
    Aug 16, 2010 1:52 PM in response to Donald Mckelvey
    Totally wacky. Same 3 blinks. Bought a new imac. Was ready to discard G5 but when I opened it up to take some cards out I said to myself "This is a beautiful computer." Then I found this thread, got out the hair dryer and VOILA!!!! Working great!! For how long is the question, I guess. My wife's happy to ditch the G4 for the G5. Thanks BDAqua!!!
  • by BDAqua,

    BDAqua BDAqua Aug 16, 2010 2:33 PM in response to moraine music
    Level 10 (123,765 points)
    Aug 16, 2010 2:33 PM in response to moraine music
    Hi moraine music, and a warm welcome to the forums!

    Great to hear, thanks!

    Just Sleep it & it may run for a long time!
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