iFixit - Active Questions With Device "Power Mac"

Power Macintosh G3 Blue and White: This one is a doozie...

Wed, 15 Oct 2025 10:57:05 -0700

I wanted to see if I could run a very early version of Linux on this Mac, so I got an installation disk for Linux. I tried to boot from the disk, to my surprise nothing was showing up on the TV that the Power Mac was connected to. No grey screen, no boot menu, nothing, even though everything else appeared to be operating fine inside the Power Mac.

Here’s what the diagnostic LEDs are showing inside the Power Mac.

Did I brick my machine by trying to boot from this installation disk? Did my graphics Card die?

Things I I have ruled out:

The VGA cable is fine, I tested it with my Mac mini and it worked.

TL;DR: Screen is black, but startup chime is present, fan is running, and 2 LEDs are lit after trying to boot from a linux installation disk.

@mayer ideas?

Is this the CUDA button I am looking for? I cannot distinguish between them. Tried pushing both of them, the one on the right made the Mac power on and off, the other one on the left made the Mac do the boot chime and made the optical drive rev up. Still no dice when it comes to the display, there’s nothing being shown. No flashing folder, no grey screen, nothing.

I removed the PRAM battery for 30+ min and that didn’t help either.

@mayer

CUDA button was a no-go. I left the PRAM battery out for a full day now, thats a no-go too. Boots up, fans are running, optical drive operates, but no video. One thing I have noticed is before this incident happened, on boot up ALL of the LED’s on the logic board either stayed lit or blinked after booting up. After the linux incident only 2 of the 4 LED’s stay lit after the initial boot up. Could this be a sign?

I am leaning towards a graphics card issue. I just don’t want to be pouring money into unnecessary places.

I am afraid that this machine is a brick now. I'll try a new GFX card as a last resort.

A new Graphics Card didn’t work. This machine is officially a brick.

⟐ Answered October 15, 2025 at 10:57 MST

Power Mac G5: Unique Not powering On Issue?

Wed, 24 Sep 2025 10:36:04 -0700

Good day!

I recently bought an old G5 Powermac Dual 2.0Ghz along with a 23" Cinema Display. Model is an A1047, EMC 1969, PowerMac 7,2, made June 2003-June 2004; all based on the Serial lookup on everymac:

https://everymac.com/systems/apple/power...

Aftermarket ad-ons, which were already installed:

There is an aftermarket ATI Radeon 9800Pro 256mb Graphics Card installed. The GPU fan does spin.

There is 1.5GB of RAM (6x256MB).

It did NOT come with a hard drive, but I do have 2 working hard drives which I installed to see if I could get it to boot. One with 10.5, and one with 10.0 (although, I realize that everymac says 10.2 is the lowest it came with).

I have done research and haven't been able to find anything based on my specific problem(s):

First, and this is the weirdest based on not being able to find anything about it….when power it on the LED light turned on as the button is press; however, as soon as I remove my finger the LED turns off - yet the machine is still running. Anytime after removing my finger from the power button (meaning that the LED is off while the machine is on) if I press the button the light will turn on, and as soon as I remove my finger from the button the LED power light turns right back off (but not the machine).

There is NO chime.

The fans ARE running.

If I leave it running for about 1-2 mins the funs begin to spin very fast…it sounds like an aircraft! lol

There is NO display to the, Cinema display, which DOES work as tested through the ADC to DVI adapter to my other Mac.

Various, and working, USB keyboards and mice do not work. Caps lock will not light up, and the mice have no optical lighting underneath. Also, the eject button on the keyboard doesn't do anything.

What I have tried, based on other articles:

Power supply does click when plugged in, read in the Apple manual that good ones often do that.
Swapping the positions of the CPUs.
Running only 1 CPU on the #1 (top) CPU slot; tried with both CPUs.
Reseating the RAM.
Using different combinations of the RAM (however using the same amounts, same locations on both sides).
Removing the graphics card to see if the boot up chime will happen (read that can be a way to test if it is bad, when you don’t have an extra GC laying around).
I was able to use a paperclip to open the DVD drive, and it does closed by itself when you push the tray.
Replaced the PRAM battery.
Tried resetting the SMU by pressing the SMU reset button on the logic board.
Ensured the CPUs were seated correctly.
Capacitors look good

Note, that in all of the various combinations mentioned, the power LED light does not stay on unless the power button itself is being pressed.

What are some of your thoughts here? I feel that testing the logic board and individual CPUs with ones known to work would be the next best approach; however, before going out and buying anything I thought I would see what others thought!

Hopefully, this can help someone else too!

Thank you for any help you may provide! :)

⟐ Answered September 24, 2025 at 10:36 MST

Power Mac G4 MDD: Power On, fans spin up, power light on 1 second then off

Fri, 22 Aug 2025 11:15:23 -0700

I recently acquired a Power Mac G4 1.25 MDD 2003 era machine. Top-notch cosmetics and I had plans for good Mac times here. But, instead my "new" MDD is suffering from this problem: 1) Attach power cable & DVI connection to Samsung LCD display & USB connection to Apple brand full size keyboard and the optical mouse; 2) Touch the power button above the mirror drive doors; 3) the power button illuminates for just 1 second and then immediately goes back off; 4) Fans spin up - low hum at first, and then the full "wind tunnel" effect; 5) no image appears on the LCD display, and the G4 does not respond to any keyboard commands; 6) I have let this G4 run for several minutes, but no change in the power light status and no responsiveness / output. I have reset the PMU, and did perform a full upgrade of RAM to 2GB OWC 333 MHz and dropped in a fresh PRAM battery. I have reseated the NVIDIA AGP graphics card. Looks like a trip to the 1 local Apple Specialist in a large Midwest metro is on tap.

⟐ Commented August 22, 2025 at 11:15 MST

Power Mac G5: Help Identifying a Part from a G5 PowerMac

Mon, 28 Jul 2025 08:59:21 -0700

I'm currently reassembling a 2005 G5 2.0 GHz DP, M9747LL/A.

I have the following part but I can't remember where it came from, and I've not documented it in my photos I took during disassembly.

Can anyone help identify it?

Thanks.

⟐ Commented July 28, 2025 at 8:59 MST

Power Mac G5: Side panel wont open

Thu, 17 Oct 2024 06:47:40 -0700

The lever on the side of the mac wont come out fully, and because of that i cannot open the side panel. Any tipps to how I can fix this?

⟐ Answer accepted October 17, 2024 at 6:47 MST

Power Mac G4 Cube: My stand is broken into 3 pieces. Can I replace?

Wed, 14 Aug 2024 14:16:39 -0700

stand broken can I repair

Power Mac G4 Quicksilver: With A AirPort Card Inserted, There is just a Black Screen.

Thu, 27 Jun 2024 09:09:13 -0700

So Whenever i insert my AirPort Card Into The Tower, A Chime Does Happen, but it shows up with a blank screen, and whenever i take the card out, it works perfectly fine, How can i fix this issue?

⟐ Answered June 27, 2024 at 9:09 MST

Power Mac G4 M5183: Best way to test the stock hard drive

Sun, 14 Apr 2024 22:17:15 -0700

I picked this up due to a power issue, essentially taking a chance. I had a window to power test it and after I removed a common failure point the machine powered right on. However it has a Maxtor 20GB hard drive that is original to the machine. It doesn't say what it is being OEM but it looks like a DiamondCrash 10.

Given I know Maxtor drives have a reputation what would be the best way to test it against failure on this Mac?

The video card works. YES.

⟐ Commented April 14, 2024 at 22:17 MST

Power Mac G4 Quicksilver: Is it possible to put leopard on my G4?

Sat, 06 Jan 2024 12:45:09 -0700

I have a dual 800 system and i was wondering if there was a way to up the speed without buying a new processor so i can install Leopard on my system.

⟐ Commented January 06, 2024 at 12:45 MST

Power Mac G5: My Power Mac G5 has a blank hard drive and I have a G drive with the O

Tue, 26 Dec 2023 09:53:36 -0700

My Power Mac G5 has a blank hard drive and I have a G drive with the OS Tiger On it. How do I transfer it into my Mac?

⟐ Answered December 26, 2023 at 9:53 MST

Power Mac G4 MDD: I have a power problem on my FW800

Fri, 20 Oct 2023 20:55:04 -0700

Sorry for posting on such an old thread, but i have a power problem on my FW800. Started months ago, and i have swapped the power button board assembly and cable, then the machine started. But that didn't last long. After a short while same thing, and i swapped the second button board with the original, and surprisingly it all went ok for a little while again.

Current status is, pressing the button light comes on instantly, and that's all. My understanding is that all MDDs carry the same PSU? A tech guy suggested measuring amperage of the power supply. How do y'all measure voltages by the way? Is it correct that the psu needs to be plugged on the mobo?

Thanks in advance!

⟐ Answered October 20, 2023 at 20:55 MST

Power Mac G4 MDD: Is there a fuse for this?

Fri, 20 Oct 2023 10:16:17 -0700

My monitor cable came loose on a PowerMac G4 and then the machine shut off and won’t start again. Feels like a fuse problem but I can’t find anywhere that describes where a fuse might be?

⟐ Answered October 20, 2023 at 10:16 MST

Power Macintosh G3 Blue and White: What are these 8 pins on the back of the cpu

Wed, 11 Oct 2023 11:11:35 -0700

Cpu says XLR8 MSG4Z400 I’d like to overclock this but cant figure out how

⟐ Commented October 11, 2023 at 11:11 MST

Power Mac G5: Possible G5 graphics card replacement?

Wed, 13 Sep 2023 05:50:36 -0700

Hello! I'm was trying to pull all the data off of an old Power Mac G5, and while the computer powered up just fine (fan running, audible responses to key strokes, etc.), I discovered the monitor (an old Mag InnoVision LT976s from 2003) no longer displays anything. To be clear: the monitor powers on, and displays options, etc. But it indicates it can't detect a signal from the computer.

Undaunted, I bought some new cables (VGA to DVI, DVI to DVI, etc.), and even (thanks to this site) tried my hand at removing the (very dusty) video card, wiping it off a little, and putting it back in. No dice.

As such: is the only option here to hunt down a new video compatible with an old G5? If so, does anyone have recommendations on what to buy? Note: I only need it to help me get the data off the computer, not to work particularly well or for the long haul — so it doesn't need to be particularly nice.

Any recommendations are welcome!

⟐ Answer accepted September 13, 2023 at 5:50 MST

Power Mac G4 Quicksilver: How to connect PMac G4 QS to a MacBook late 2009 model?

Sun, 20 Aug 2023 23:58:47 -0700

I have both machines from the title and would like to know how to connect them together so I can at least get in QS from a macbook.

⟐ Commented August 20, 2023 at 23:58 MST

Power Mac G4 Cube: What optical drives from other Mac devices can be used in replacement?

Sat, 19 Aug 2023 21:14:51 -0700

I just got a Cube, and it ate my Tiger disc. If someone knows how to get it out it'd be much appreciated. Anyways, it looks like this optical drive is dead, anyone know a fix or a replacement? I have $@$* tons of old iBook G3s, G4s, a Power Mac G4, a Power Mac G3 (Server), and a Power Mac G5. Also some 2006 and 2009 MacBooks, and 2010 and a 2012 MacBook Pro

⟐ Commented August 19, 2023 at 21:14 MST

Power Mac G5: Power light blinks twice, fans high

Mon, 07 Aug 2023 10:56:05 -0700

I know this type of question has been asked here but id like to explain my issue.

Power Mac G5 has been sitting on the shelf of a business for at least 3-4 years with no use or ever being powered up. I get it today and power it up but immediately the fans run high and theres no video on the screen. The power light blinks white twice constantly.

I took out all of the ram - same exact thing (and no beeps even).

I take out all the ram and pram battery - no change.

I held the pmu button - no change.

What am I probably looking at? May just need a new pram battery since it was sitting dormant for so long? logic board? psu?

any help is appreciated.

⟐ Commented August 07, 2023 at 10:56 MST

Power Macintosh G3 Blue and White: Power Macintosh G3 Freezes on Startup—What Should I Do?

Sun, 06 Aug 2023 19:55:55 -0700

I bought a fully functioning Power Macintosh G3 a few months ago that came with an OS 8.6 CD, and booted up again for the 2nd time today to try and connect to ethernet wifi. I got the error that "Internet Setup Assistant" isn't installed and I didn't know how to install it. Ran disk utility on the hard drive and said it had minor errors so I repaired it, and while I was running disk utility on the CD after it froze so I restarted. Seemingly everything was working fine when I started it again, but it froze when I tried to open Extensions Manager so I restarted it again. This time I got a message upon startup saying that it was doing disk utility on my hard drive since it detected a crash, but the progress bar hung in the middle so I restarted it again. And this time (and every attempt I've made at starting it after that) It just freezes on startup like with a blank box over the words "MAC OS 8.6". I'm sorry for the longwinded explanation but I'm freaking out here and don't know what I should do. I've tried holding down the C key as well as the Command + Option + P + R key while restarting (don't know if I did it properly) but it hasn't worked. Please let me know if you have any idea what I should do please, and thank you so much for taking the time to read this!

⟐ Answered August 06, 2023 at 19:55 MST

Power Mac G5: won't power on, I just smack the machine and then it powersup

Mon, 24 Jul 2023 15:18:30 -0700

I have similar issues , it seems to be a cold/cracked solderjoin somewhere , I just pull plug , drain caps , replug , sit 20m so caps will charge then power-up , if no reaction i just smack the machine and then it powersup. (eventually). - Unable to determine location , may be in the PSU(the issue).

⟐ Answered July 24, 2023 at 15:18 MST