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Technology (Apple) Businesses Apple Hardware Technology

Apple G4 Power Supply Woes? 152

Posted by Cliff from the don't-taunt-happy-fun-power-supply dept.
Predius asks: "I, like many others based on forum hopping, have an Apple G4 desktop that has decided it no longer wishes to power up. I've replaced PRAM batteries, verified power supply voltages, pressed the CUDA switch, and done combinations of the above. Trying to start it just results in a blip of the powersupply fan and the power led on the motherboard flashes once. Every now and then it will actually boot, and when it does it's 100% rock solid, will reboot fine, etc. If I power it off, I get to play games again trying to power it up. Does anyone know how to manually start an Apple Gigabyte or later rev power supply? Standard ATX power supplies can be fired up by shorting the green PWR ON lead to ground, but Apple decided to be different. I await the collective's wisdom."
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Apple G4 Power Supply Woes? More

Apple G4 Power Supply Woes?

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  • Blinkerfluid (Score:4, Funny)

    by Anonymous Coward on Wednesday October 08, 2003 @04:12PM (#7166122)
    Did you check the blinkerfluid?

  • Humidity (Score:2, Interesting)

    by buback ( 144189 )
    I have the same problem with my pc. I've had it since july, and i think it is based on humidity. when i crank the AC up in my room and close the door, it will take about 20-30 mins before it will start. it's not the temperature because it can be 60 degrees in the room, but will still not start if the humidity is too high.

    • Re:Humidity (Score:3, Informative)

      by Anonymous Coward
      A quick blip of the status light on a Macintosh can idicate a power short. It could be a wire in a supply lead has been exposed and is intermittently contacting the metal chasis, or the power supply has an internal problem.
      • Yeah or maybe a screw or other metal debris in one of the slots. I think it's called a stirrup circuit, cuts out a switching power supply when the demand for current exceeds the specs of the supply.

        Or it could be this:

        An experience I had recently with my mom's G4 is the display was going dim near the bottom (17" Apple Flat Panel, ADC-style). Remembering the enormous contacts on the video card (to deliver power to the monitor), I thought maybe some oxidization created some resistance, thereby cutting the a

  • Inrush current (Score:5, Informative)

    by morcheeba ( 260908 ) on Wednesday October 08, 2003 @04:22PM (#7166214) Journal
    Sounds like this may be a inrush current problem... maybe something is taking extra juice to start up, or the supply can't deliver the initial kick. A multichanel scope would help a lot to see that all voltages are getting to where they need to be in a reasonable time. Otherwise, try removing everything that you can and see if it comes on (drives, ALL ram, usb, pci cards, modem, etc.) - maybe eliminate it that way. Remember, a bad card (one that's drawing too much current) may not cause the system to fail until another good card is inserted and pushes the power supply over the threshold.
  • The last time a Mac did this to me it turned out not to be the power supply, but the battery that was bad. Note that this wasn't a G4, but an older PPC 604 model, so things may be different. For some reason when the battery was dead the machine wouldn't turn on, or when it did it would turn right back off. I'd replace that first because it's an easy and much cheaper fix.

    -David
    • While granted, that might help, the poster did kinda say they the PRAM Battery Replacement was the first thing to be done.
      • While granted, that might help, the poster did kinda say they the PRAM Battery Replacement was the first thing to be done.
        Oops. Smacks head with dazed look on face. Sometimes one sees what he wants to see and completely misses what is in front of him. :-)

        Ah well, it's a new day tomorrow.

        -David

  • corrupt PMU? (Score:5, Informative)

    by Lizard_King ( 149713 ) on Wednesday October 08, 2003 @04:25PM (#7166252) Journal
    Have you tried resetting the PMU?

    Pop that sucker open (unplug first!) and there should be a little black button on the lower front of the logic board. "Reset pmu" will be printed on the board somewhere near the button. Push it for one second and only press it once. Let the box sit for roughly 5 minutes unplugged and then turn it on.
    • sorry for the acronym abuse =) PMU == Power Management Unit
      • On the newer Macintosh computers (Blue G3 and above) you must be sure and press the button only once and for less than a second; if you press it more than that it will crash the PMU and the battery will die within a day or two rather than several years. The machine will still power on just fine, and you won't know anything bad happened, but the battery will be toast. Also, after you press it you only need to wait about 15 seconds. This info is straight from the Apple service manuals for those computers.
    • macintouch.com has great forums on Mac issues, i would say look/ask there or some of the Mac tech help mailing lists.

      i know some older motherboards required you to hold the motherboard reset button for about 30 seconds if you ever pull the PRam battery out.

      back to your first issue of manually jumpstarting a powersupply, dunno. sorry. just figured iw ould mention the motherboard reset button because i know somebody that got a lot of stress from not knowing that.

    • Re:corrupt PMU? (Score:3, Insightful)

      by bluethundr ( 562578 ) *
      Pop that sucker open (unplug first!) and there should be a little black button on the lower front of the logic board. "Reset pmu" will be printed on the board somewhere near the button. Push it for one second and only press it once. Let the box sit for roughly 5 minutes unplugged and then turn it on.

      That sounds like the procedure we used to do on the old pre-blue-n-white PPC macs. Is this 'PMU' button another name for the CUDA button? I haven't seen a mac motherboard in a while. Even the most knowledgable [bothell.edu]
      • Yes, this link [applelinks.com] explains a lot. Don't bother reading the comments - they all talk about Chrysler cars.
      • This little button has saved my ass many times, especially in a PowerMac 5500 I had which needed it pressed every time you changed a PCI/CSII card, RAM, HDD etc.. sometimes the video modes would screw up and only let me use 800x600, but the CUDA button fixed that.

        ObSlashdot: I, for one, welcome our new CUDA leaders.

      • CUDA and PMU are effectively the same for end users. Certainly CUDA was the code name for the chipset responsible for your Mac's power management in eariler PowerMacs. Since then the PMU term has come into use. A new chipset? Certainly grown more functional since those first releases.

        The button resets a set of values the PMU chipset contains or at least manages; including auto start-up and shut down times.

        We use its functionality in DssW Power Manager [dssw.co.uk].

        DayStar have a TechNote regarding reseting CUDA on

    • On some of the older models, you had to hold the button down for 15-30 seconds for it to work. But like he said, only press it once.

      And i know you said that you verified the incoming voltage, so my only other trouble shooting suggestion would be to try it at a friend's house or at work.

      I would be frustrated as hell if that happened to me. Almost as pissed off as I am about my Win2K notebook being unable to boot (hive file) after running a windows update. Just another reason why I love my G4 & jagwi

    • Re:corrupt PMU? (Score:3, Informative)

      by macmurph ( 622189 )
      When you reset the PMU/CUDA, be sure to only press the button once. Apparently, if you press it twice, you have to wait several hours before the machine will start.

      Also, it sounds like this guy may have a well known problem with his power switch. The small PC board behind the powerswitch in some G4 towers was defective and needs replacement. Its covered under warranty from apple.

  • Hmmm, maybe... (Score:1, Flamebait)

    by SandSpider ( 60727 )
    ...maybe you should, I dunno, take it in to be fixed. No, really, you've tried diagnosing it, and you couldn't figure it out. So, rather than take it in to be repaired, you decide to post your question on Slashdot? Seriously?

    I mean, I guess that works for the editors, since you post made it up, but I don't think that this is such a common problem that it needs to be here for everyone to try to help with.

    But since we're here, could anyone tell me why my Check Engine Light keeps coming on in my car? Also, t
    • Also, there's a hole in my shoe that I've tried patching with duct tape, but that doesn't seem to work - any advice on that?

      two words for you: shoe goo!

    • This isnt techtv, we dont want to see the same old bs.
    • this question is ways better than the usual dope on ask slashdots(that can be either solved by a quick googling, or are impossible to fulfill in full).

      this is slashdot so we do like to hear about exotic woes such as this... and we do have old shit puters around as well. and being geeks we enjoy reading problems like this and reading other peoples answers to them, otherwise you could just stick to your local newspaper for source of info.

      take it in to be fixed? yeah, that's real good advice, obviously if he
    • People write in with their car problems to the auto mechanic column in my local paper all the time, with good results. I don't see how this is any different, as long as you can separate the wheat from the chaff.

  • Aggravating problem (Score:5, Informative)

    by Mulligan ( 29951 ) on Wednesday October 08, 2003 @04:34PM (#7166358)

    Especially if you are out of warranty. Apple describes it in support article 95039 [apple.com]. The most frustrating part is that replacing the power supply is the last step -- they try to replace the CPU before checking the power supply. This means that you have to commit to purchasing a CPU if it is the problem child. My CPU (500Mhz G4) was ~USD900 last time I checked -- more than the value of the the computer at the time. All this is after you pay their diagnostic fee.

    Don't get me wrong, Apple Care is wonderful, but once it expires you can be in for some expensive repairs...

    • Err, if the CPU is the problem, then you'll have to replace it anyway, regardless of the order things are checked in. How is that a frustrating problem on Apple's part?
      • It's aggravating because the power supply is a lot cheaper, presumably, than the CPU. When troubleshooting comes down to replacing suspect parts, and you must incur the cost of each part you replace, it makes sense for the consumer to determine the most likely suspects, then replace the cheapest suspect part first.

        On the other hand, Apple suggests that you replace a significantly more expensive part BEFORE replacing a relatively less expensive part. That's not a cost-effective way of fixing the problem, al
        • Umm... is there some reason that your machine wouldn't qualify for a flat rate repair?

          • Umm... is there some reason that your machine wouldn't qualify for a flat rate repair?

            Yes, because normally when you get something repaired, you pay for two different things:

            Parts

            and

            Labor.

            In this case, the "part" a CPU, is a very expensive part indeed.

            Flat rate repair in cases like this would be bad, because it would have to be very high to cover the poor shmucks who have to have their CPU repaired. So, the flat rate for fixing a computer with a power supply problem would cost $1050 if the CPU neede
            • The reason I mentioned it is that, at least for laptops, Apple charges a flat-rate fee for service, assuming that there is any real hardware replaced. I don't know if that is the case for desktops, though. Worth asking about, anyway, as it might end up being cheaper to go that route if that is the case. At the very least, take it to a "genius" and see if he/she has any ideas.

    • For $500, you'd get a 1.3GHz G4 upgrade.

      Here's a list [macsales.com] of what MacSales says will fit into a G4/500 Sawtooth Mac.

      800MHz upgrades are about $250.

      If the warranty is already expired, this is way better than getting the same processor again.

  • Obvious? (Score:5, Insightful)

    by YouHaveSnail ( 202852 ) on Wednesday October 08, 2003 @04:35PM (#7166372)
    I hate to ask the obvious, but since your machine is clearly working improperly in a manner that cannot be due to software, OS installation, disk formatting, etc....

    Have you considered taking it in for service?

    The friendly folks at the nearest Apple Store will be happy to take a look at it. If it's still under warrantee, or if you've invested in AppleCare, it won't even cost you anything.

    • Re:Obvious? (Score:2, Interesting)

      by andcarne ( 657052 )
      You might be surprised. Sometimes they wil even do free service on out-of-warranty products if its a 'known issue'. My 5-year-old Blue&White G3 monitor died a few months ago. It was making sparking noises and a funny smell when you turned it on. I called Apple up, they said it was a known issue and shipped me a new one for free. It sounds like you are past the point of being able to fix it yourself. If you haven't already, try checking the Apple Knowledgebase, and removing cards as was suggested a
  • "If I power it off, I get to play games again trying to power it up."

    Sounds like Apple's game library noticably expanded!
  • "I've replaced PRAM batteries, verified power supply voltages, pressed the CUDA switch, and done combinations of the above."

    Look, there are many ways a powersupply can fail and still appear to have the correct output voltages. For instance, the powersupply has a power good signal going to the motherboard. The PS determines whether it's within its specifications, and when it is (some mS after actual turn on) it asserts the signal, and the motherboard comes out of reset. It could be that either the powersupply is not asserting the signal correctly, or that it is still out of spec.

    But it could be a dozen other problems. Until you swap it for a known good PS, you cannot know for sure that the PS is good. (other than, perhaps, putting it in another good system and powering it up there)

    Here [haertle.ch] is the pinout of a dual G4 powersupply. I suspect that the pinout is substantially similar. You may be able to force the PS on, but you'd have to find and assert the power good signal (I doubt that the supply doesn't have one - chances are they made this pinout with a multimeter, and there's no easy way to find the power good without a scope or analyzer)

    But I suspect that you'll spend less money and time by simply getting a new PS and replacing it.

    Please note that powersupplies contain many parts that fail over time. Aside from the obvious fan, the electrolytic caps eventually dry out, causing out of spec voltages, out of spec ripple, and out of spec regulation. You won't be able to see the ripple on the average multimeter.

    Also note that computer hardware troubleshooting is a black art, and should only be practised by mages trained in this specialty.

    -Adam

    • It's not so simple to just drop a new power supply into a Mac. The supply on the G4 Powermac is not, as far as I can tell, identical to or compatible with the standard ATX supplies that x86 machines use -- the part in question is both proprietary and expensive. Your advice would be perfectly reasonable if we were talking about an x86 box, but we aren't, and there's the rub.

      I had a G4 that refused to boot, and when I brought it to Microcenter to be repaired they informed me that if it was a bad power supply

      • My G4(2x867MHz,MDD) has exactly this same problem. I've reset the PMU -- it makes no difference. I've even taken it to the shop twice. Of course, it's always working by the time it gets there. :) It seems that by the time it cools off, it works fine again.

        I also have the new (supposedly quieter) power supply for the MDDs. I haven't installed it yet because I'm afraid to add another variable to the equation.

        Their advice in the shop: buy AppleCare -- we can't find it, but it'll probably be back!
  • I've been looking to get a G4 rather than a G5 because of the large number of drive bays available in the G4 case (video editing). Could it be that the power supply doesn't have enough power to spin up all the drives in your system simultaneously?

    If this is the case, TiVo hackers came up with a device to allow some of their units with less powerful hard drives to spin up two drives separately: the PTVupgrade SmartStart Power Supply Protector [9thtee.com].

    I have not used this device myself yet in a TiVo or Mac, so I c
    • Slightly OT, but if you're planning on getting a G4 over a G5 just because of internal drive expansion capability, you should think again.

      If you are seriously interested in video editing, you'll want to get external firewire drives instead of internal IDE drives. You can plug in a huge number of the external drives, many more than you can fit in the case (or on the macs IDE controller) and software RAID them together. I'm a consultant who specializes in these things, and FireWire software RAID for video da

      • If you're capturing video from another firewire device (say, digital camera or miniDV deck), the video will move directly accross the bus with less system overhead, resulting in a much more stable configuration.

        This is incorrect. Firewire mass storage doesn't talk to firewire video-- completely seperate protocols. It requires CPU intervention to figure out where to write things on the disk, etc. All you'll succeed in doing this with recipe is increasing resource utilization on the firewire controller.
        • Theoretically true, but real world experience -- at least on G4/G5 systems -- speaks otherwise. I'm not entirely sure why, in part because I'm no system programmer, but you can go ahead and try it. Since this is a line we've been feeding our clients for a year now, some of my staff and I ran some crude benchmarks this morning (always fun to do on a working saturday...)

          Take a miniDV camera, (or a Digi002 audio interface which also uses firewire) and check the CPU utilization and memory overhead (on a mac) w

    • Ugh- as an electrical engineer, that smart start product looks dangerous.

      Two problems:
      1. It ramps up voltages. This usually isn't a good thing for digital logic - it means its going to spend some time at a marginal voltage level. Hopefully this ramp is fast.

      2. It sequences the seperate power supplies without sequencing the logic. When you've got something connected but not powered, the signal lines power the chip through protection diodes - the effect is that the IDE controller is trying to power the driv

  • Power issue from motherboard (Score:3, Informative)

    by esammer ( 309397 ) on Wednesday October 08, 2003 @05:21PM (#7166781)
    I have a G4 Dual 400 (mirrored drive door) and had a similar problem. After numerous games, and since it was still under warranty, I brought it in. Four visits to my local Apple store later, it works. They replaced the power supply, memory, ram, processor, and finally after I demanded it, the motherboard (or "main logic board" in Apple lingo. It was the motherboard.

    Turns out there's a known Apple TechNote on the mirrored drive door boxes that produces a power on, but unexpected results type problem. Here's the technote (iirc) or at least one similar: http://docs.info.apple.com/article.html?artnum=950 38

    I HIGHLY recommend making a list of technotes that directly refer to and explain the problem in detail. Do what you can yourself. Go to an Apple store (make it a road trip if there isn't one near you - I'm in NY, US so it wasn't a problem), walk up to the "Genius Bar" and make them work for their famed support reputation. I've owned macs since sometime prior to the Quadra and when it doubt, Apple *will* save you should you ask the right way. Be nice. Beg. Your warranty is an intangible and can be extended by the manufacturer if it is a known problem and you plead your case correctly.

    This is usually related to a bit more than the power supply and is absolutely a known issue.

    Good luck. Chin up... and beg if you're out of warranty.
    • Okay, maybe it's just because it's late at night and I'm feeling cranky, but is there any reason why you couldn't just make that URL a link.

      It's really simple. Here's how you do it:

      <a href="url goes here">link text goes here!</a>

      In your case, you might have written something like:

      Here's the

      technote [apple.com] (iirc) or at least one similar.

      Which is coded this way:

      Here's the <a href="http://docs.info.apple.com/article.html?artn um=95038">technote</a> (iirc) or at least one similar.

      The ma

  • Dude. It sounds like you simply have a blown-out power supply.

    This happens ALL THE TIME with PCs. Of course, Apple has much tighter quality control, so this happens a lot less, but does happen nonetheless (I've seen several iMacs and G4 towers with dead PSUs).

    Power supplies can die due to manufacturing defects (specifically cheap electrolytic capacitors), or due to bad power. If your building has bad power (you probably don't even know it), the life of your power supply will be easily cut in half (cons
    • Why doesn't apple just use standard ATX power supplies? They already use standard PCI, SATA/ATA, AGP, Memory, and other components, so why is using a standard power supply such a big problem?
      • I don't know Apple's reasoning, but I can think of at least one really good reason not to do so.

        When companies start using power supplies with standard connectors, it greatly increases the odds that some unscrupulous service center will start cutting corners and using non-Apple parts that may or may not meet the same specs for wattage, DC quality, or audible noise, particularly for out-of-warranty repair.

        This in turn could lead to surprises a few years down the road, and depending on state laws, it migh

      • Apple's power management and start up routines 'requires' their proprietary power supplies. Would love to be able to use ATX power boxes. Makes it real easy to build a drive or CD tower in a 9600 box, having enough watts.
      • Because 97% of power supplies don't come in the long and squat form that fits nicely in the top of a G4 tower.
      • Current G4/G5 systems like to provide power for ADC displays through the connector on the video card. The supplied voltage is 28v. So they'd either need to put DC TO DC converters on the motherboard to step up one of the avaiable voltages, or just let the power supply handle it. Having the power supply handle it also gives them a convient method of requiring Apple parts in their boxes.
    • "This happens ALL THE TIME with PCs. Of course, Apple has much tighter quality control, so this happens a lot less"

      Then why are my PCs all running fine after 2-7 years but my G4 died after 18 months?

  • Take the battery out and let the computer sit unplugged for a few hours. Then put the battery back , plug in power, and test. If this doesn't work try with the battery out overnight. I try this after everything else fails and was very happy to find this fix.
  • 1) Reset the Tralfaz Emulator
    2) Hold the Grimes Conductor & the Simpsons polylead together
    3)...
    4) Profit!
  • ...technical support queries. Pay for your own Apple Care and leave /. for the quality reporting that it provides.

  • How old is the machine? (Score:4, Informative)

    by gozar ( 39392 ) on Wednesday October 08, 2003 @07:14PM (#7167624) Homepage

    There was a revision of the G4 in August, 2000. The first ones off the line had power switch problems, giving almost the same symptoms. We had them all replaced under warranty.

    One work around, find an older Mac USB keyboard that has a power button on it. Plug it in and see if the machine will start then. If so, you will need to get a replacement power switch.

    More info available from ZDNet [com.com].

  • Replacement (Score:2, Informative)

    by AdamBLang ( 674002 )
    My Power Mac G4 is on it's second power supply. The problem went away! And it's a Power Mac Gigabit, not Gigabyte.
  • I have had several issues like this. A factor to include is the Video card...if you have an Apple Studio Display attached to it. The ADC Connector provides 28V DC, I have seen an improperly seated video card or a loosely connected ADC connector cause power supply failure.
  • Don't know about G4s or desktops, but I'm now on my third dual-USB iBook external power supply. First replacement was covered by the warranty, but I just shelled out ~$85 for the second replacement today at the local Apple store. And the main logic board had to be replaced three months in. AND the little twist lock on the underside that releases the battery is broken and held in place with scotch tape. I love this laptop, but the build quality is not good.

  • Easy... (Score:4, Funny)

    by MasonMcD ( 104041 ) <masonmcd.mac@com> on Wednesday October 08, 2003 @08:57PM (#7168207) Homepage
    just push it downhill, press the power button, and pop the clutch.
    • I wouldn't have thought such a puny core as a G4 could have so much back pressure, but they do! Damn thing locked the tires at 35mph using 5th. It wouldn't have been so bad but it's a FWD design. THAT was an interesting ride. Thinking I could out wit Jobs, I tried it going down hill backwards, tranny in reverse. Imagine my surprise when I discovered reverse was meerly a placeholder, and wouldn't be available till 10.3 shipped, and the brakes don't work unless the cpu is running, 'cause who'd need to st
  • This sounds like the cheap capacitor problem that was affecting PC motherboards last year. My ABit KT-133 was experiencing the exact same symptoms you describe, it would work fine until I turned it off, and then it was a crap shoot if it would boot up again. Here's the /. article: http://slashdot.org/article.pl?sid=02/11/04/17512 1 0 I know it's an Apple, but if you can get a look at your capacitors, on the motherboard and in your power supply, see if they have bulging tops or any leakage. Mine were ju
    • Part of the cap problem last year was that a trusted manufacturer of parts in Taiwan, used by lots of computer manufacturers, including Apple, was hit with a shipload of bad capacitors. I think the info I read on it was that they came out of China. If you have an older Airport base station and it's wacked (lights come on but don't flicker or signal what's going on) you can get replacement caps from a local electronics supply place and repair the Airport yourself, if you're a good hand with a soldering iron.

  • It was indeed the power supply in my case (Score:4, Interesting)

    by Predius ( 560344 ) <josh.coombsNO@SPAMgmail.com> on Wednesday October 08, 2003 @10:07PM (#7168657)
    After submitting the question, I resumed scouring the web and got a bit braver with my parts...

    After reading up on some G4 to PC ATX case conversions, and doing a lil guessing, I determined that the G4 power supply should use the same power up sequence as an ATX. What threw me off is earlier PC ATX power supply to mac conversions had to invert the power on signal, and I incorrectly assumed Apple did the same with the G4.

    http://www.xlr8yourmac.com/systems/ATX_G4_AGP_co nv ersion/G4_AGP_to_ATX_case_pg2.htm has the mods that get you 99% of the way there, you just need to supply 28v to finish the job on any ADC capible G4s. Once I figured this out I had the system booting off a PC power supply (and the 28v trickle from the G4 supply). I bench tested the G4 supply, and sure enough, shorting the power good, which should have fired it up just bliped the power. Based on the symptom set, it seems pretty likely this is whats affecting others. The test is simple, use a paperclip or something similar, short the green power up line to a black ground line, and see if the power supply fires up. If it does, it's the mobo, if it doesn't, its the power supply. No more throwing batteries sacrifical virgins at the problem while performing dark rituals around the CUDA switch.

    And for those curious, the machine I'm building is a FrankenMac, assembled from random bits on eBay and my parts closet. I've TRIED talking to apple stores, but the instant they figure out its not a boxed apple, they tell me to pound sand. I've got $75 into the power supply, so I wanted to be ABSOLUTELY certain it was the culprit before canning it. Unfortunatly, while Apple will offer some simple diagnostic guidelines, they won't give you all you need to do this sort of work outside of an Apple authorized repair depot.
    • the machine I'm building is a FrankenMac, assembled from random bits on eBay and my parts closet

      Ahh... key factoid that was missing from the original question. Invalidates all of the comments that advise pulling the warranty trigger.

  • this fixes my g4's boot problems every time
  • It's your front panel board, which is a user replacable part. Check article id 58748 at Apple Support.
    • Actually, it NEVER was the front panel board. If you research what Apple did handling those cases, if under warranty that is... They would replace the front panel, as well as the motherboard and power supply, 'just to be sure' in one shot. If you were out of warranty, you were SOL as many had replaced the front panel board after refrencing that article, with no luck. Given that the board itself used pulls $50 dollars for a part that doesn't fix the issue, the thought of spending $150+ on a power supply,
      • I read how you solved the problem after I posted. Boy is my face red! I still think everyone else is a jerk, though! =) I'm curious as to how you adapted the ATX PS. You'd be my hero if you posted details, since I have yet to find instructions on converting a PC PS for a gigabit G4.
        • It's a two wire modification to the PC ATX power supply, plus you need a 24v/28v source.

          http://www.xlr8yourmac.com/systems/ATX_G4_AGP_c o nv ersion/G4_AGP_to_ATX_case_pg2.htm#next

          That details the modifications needed to get 20 of the 22 pins correct. Apple used the same connector keying on the 22pin header as the normal 20 pin ATX header, so your connector will slot right in where it needs to. Once you have that, you need to supply 28v, which is a task I leave to you. Right now I'm using lamp cord press
  • Did you even bother to do any research first before posting here? theres dozens of websites that have instructions on adapting an ATX powersupply to power macs.

    TRY GOOGLE.
    • Yup, I did. If you read them all, you'll see they all discuss Yikes/Sawtooth era G4's, and G3's, which used 20pin connectors with no 28v provision. The others are for earlier PMs that differ a bit more (inverted power on signals, etc) so while the info is good, it's not directly applicable. A few mention that Gigabit and newer systems that support ADC connector sporting video cards have a different (22pin) connector and require 28v, but don't go into any further detail. It's left to the experimenter to de
  • I had a similar problem in my car - I turn the key and it would just click and do nothing, but sometimes it would start, and then it ran solid, until I powered it off. On good days it would start right away, but sometimes I really had to play tricks to get it going.

    Turned out I needed a new starter. I'd check the starter on that thing. May be it just needs a new solenoid.
  • ...on my 2x800Mhz. Very disturbing as it was only 18 months old and all my cheap ass PC power supplies are going strong, supplies that are anywhere from 2 to 7 years old. I had my local independent Apple shop replace the power supply and everything seemed to be ok until I had it on for an hour and it just powered off suddenly. It seems that it is getting hot and shutting off. All the fans seem to be working well but it won't stay powered on for more than an hour or two. I haven't had a chance to take i
  • 1. Try (Command + Ctrl + Power key) 2. Pull all third party RAM and cards. 3. Hit the reset switch on the logic board. 4. Replace the battery. 5. Reset the PMU. 6. If you successfully start the Mac, press (Command + Option + O + F) and type reset-nvram. press type set-defaults. press type reset-all. press hth, dion
  • I know this won't be of much help, but i've seen countless problems that can cause these issues (in both Macs and PCs). My own PC did this very thing to me about a month ago....changing the power supply fixed it right up. I've also seen a mac with a bad mobo that exhibited the same problem. As for other causes, i've seen bad bios chips, shorted wires, swelled mobo capacitors and bad house outlets or power cables. In short, take it somewhere. Either and applestore, or an authorized service center (i'm l
  • Dear /.ers,
    Like undoubtedly many anal retentive, abbreviation savvy others have done before me, I searched like a devil to find the meaning of what I then thought to be an acronym: CUDA. However, no such definition was to be found, and this is very rare.

    On further inspection, I also found that Apple _consistently_ referred to the controller chip as Cuda, not CUDA, further strengthening someone else's theory that this is indeed a code name/nickname of some sort and not a pronounceable initialism (a.k.a. acr

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