G5 battery fixes boot failure

      10 Comments on G5 battery fixes boot failure

A note to help the next person trolling Google looking for a clue…

g5inside.jpgA month or so ago we had an older 2.3GHz PowerMac G5 just refuse to boot. Well, that’s not quite right, it would begin booting…startup chime, disk spin-up, grey booting screen…then a little patch of color appeared in the middle of the screen…then nothing…after a minute, the fans would jump to takeoff speed.

I swapped out the video card (mistakenly thinking the little patch of color in the center of the screen perhaps meant the video had failed). Nope. Reseated, then tried swapping out the memory chips. Nothing.

I booted the machine in target mode (holding down the “t” key while turning it on), ran a firewire cable between the G5 and my laptop, and transferred important data off the recalcitrant machine. This seemed odd—it would boot into target mode and let me access the internal drive but it wouldn’t boot into the OS?   Well, if it can get almost there (function as target drive) surely it will boot from a installation disk.  Nope.

At this point I figured it was a motherboard problem and with Apple that’s very close to being the end of the matter (good luck finding multiple sources of inexpensive replacement parts for old Macs).

Finally took out the memory, video card and drives and put those pieces in other machines. Figured it wasn’t worth spending $700 to get a new motherboard for a PowerPC box. Moved the G5 “shell” into the closet and forgot about it.

36.jpgUntil last week. I was listening to The Mac Observer’s Mac Geek Gab (I have a long commute so I follow close to 25 different podcasts—and not all technology-related, either) when there was mention of an older iMac that wouldn’t boot until the coin-like PRAM battery was replaced. Hmmm…sounded familiar. I decided to order a PRAM battery for the G5—just to see if a $5 part could revive the thing.

The battery came today in an Other World Computing box, along with 2 sticks of G5 memory (figured if this didn’t work, I could use them elsewhere). Swapped out the battery, put in the memory and an SATA drive and Voila!…it booted right up.

10 thoughts on “G5 battery fixes boot failure

  1. G4 in Hawaii

    I previously had run Disk Utilities and found that my drive had a “underlying task error on exit”. Heck if I knew what that meant. Disk Utility would not let me repair the disk. Anyway, to make a long story short. I bought a new HD from MacSales.com (OWC). Installed Tiger and did some updates and then it would hang on boot after the blue bar filled up. I did get a PRAM battery. I found your story after I bought the PRAM. I erased my drive again and it seemed to be working. But lo and behold, I started having major kernel panics. Turns out it was one of my DIMMs. I took them all out and check them one and a time. The computer chimed with the bad one (same as if there were no DIMM installed). I hope this helps someone else too!

  2. Wally Post author

    Good idea, testing a stick at the time. G5’s require 2 sticks to boot which would make it a bit more complicated but you could eventually narrow down which stick was bad…assuming you had more than 2 sticks in the machine.

  3. Chris Cardinal

    OMG!!! This fixed my problem. Sreriously, it did. I almost spent $3500 on a machine…

  4. Wally Post author

    Amazing isn’t it? You’d think a $2500 computer could come up with a way to tell you the $5 battery is going bad and it’s about to brick the machine. Glad to hear this posting helped someone.

  5. Pingback: Power Mac - Default Boot - Mac-Forums.com

  6. Hugh Rooney

    I’ve been having similar problems and was about to see how far I could toss my G5 out the window.
    I just need to find someone locally who’ll sell me a battery so I can give it a try.


  7. Nealer

    I was having random shutdowns all of a sudden on my g5 dual 2.0 June04. I discovered this solution myself and thought I’d reinforce your tip. But I didn’t even have to buy the PRAM battery. I just turned it in its cradle. The battery was not making enough contact with the contacts because of an undetectable buildup over 5 years. Turning it made new contact points.

  8. wally

    I posted this a couple of years ago and I continue to hear from people who find it solved their problem. Thanks for adding your idea–maybe turning the battery was all I needed to do 🙂

  9. Ivan

    My old 1Ghz quicksilver G4 (dual processor) went funny last week, it kept restarting when i shut it down. I reset the PMU which cured it enough to shut down, but then it wouldn’t boot. I reset the PMU again, it started up once. I had reset the PRAM, but upon testing, the battery was totally flat (0.06 V, should be 3.6), so I bought a new battery from Maplin – still no good.. OK. so I went on ebay and bought a G5 for £200. I reckoned I could just switch the disc over (I always use a secondary drive for anything other than apps) Cool. THEN, a proper Mac battery arrived and lo and behold the G4 is OK! But not quite, it starts doing this crazy restart thing. So I went alllllllll the way back and unplugged the USB hub. END of problems. That’s all it was. OK battery was dead, but ultimately, the PMU can get really upset by too much USB action, particularly from older hardware. I now have a G5, which at 5 years old is still a very good machine running 10.5.8 no probs, and G4 as backup. Old Macs Rule.

  10. Deb

    Hi all –this happened to my G5 about two years ago and I was frantic –we are a boutique agency with one G5 and I was on top of deadlines. Took it to BestBuy and their MacGeek ran diagnotics. $300 bucks later another MacGeek leaned over the counter and told me it probably was the PRAM battery. He said that BB would sell it to me for $25, but to go to BatteriesPlus and get it for $10…not that $15 was a big deal at that point…I had gone thru Mac Hell for two weeks! But, got the battery and popped it in and it’s worked beautifully…until last Friday when it started cutting out, again. So, I’m off to the Battery shop again –but $10 is so much cheaper to see if this is the problem (which I’m pretty sure it is) –Thanks for the article –this article saved my butt two years ago…!

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