IMac G5 Garbled Screen / Loud Fan / Overheating

When I try to start up my iMac G5 (pre iSight), I get the usual chime, and when the screen starts up, I get a surprise every time. Completely garbled, sometimes it looks like fog, other times like garbled information, other times like an old, badly tuned TV.
Then the fan kicks in really loudly.
I put a brand new hard drive and OS 10.5 in there a few months ago, and the machine seemed to be running fine.
Any ideas??

Your video chip seems to be failing, see if you can boot from your install disc and run Apple Hardware Test to check things out. After that, you can run Disk Utility
1. Insert the Mac OS X Install disc that came with your computer, then restart the computer while holding the C key.
2. When your computer finishes starting up from the disc, choose Disk Utility from the Installer menu. (In Mac OS X 10.4 or later, you must select your language first.)
Important: Do not click Continue in the first screen of the Installer. If you do, you must restart from the disc again to access Disk Utility.
3. Click the First Aid tab.
4. Click the disclosure triangle to the left of the hard drive icon to display the names of your hard disk volumes and partitions.
5. Select your Mac OS X volume.
6. Click Repair. Disk Utility checks and repairs the disk.
Then reboot from your internal drive and repair permissions.
however, it does sound as if your graphics chip has failed. Unfortunately, they are soldered to the logic board, which has to be replaced to solve your problem.

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IMac 27" (Late 2012) Loud Fan and Overheating Issues, causing Hard Drive Failure

Hi all,
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I have also performed a reset of the SMC as well as the PRAM, which hasn't really helped.
Any help will be appreciated. I will gladly provide any extra logs etc. if they're needed.
Thanks so much,
Alex.

Alex Cummaudo wrote:
I've noticed that the main fan will spin, on average, at 1200rpm. Is that normal? The iMac is very well ventilated and sits right next to a window...
That's the default fan speed on iMacs, so there isn't any problem with this.
Alex Cummaudo wrote:
I have also boot camped the iMac with a copy of Windows 8 so I could run some fairly power-hungry games. I intentionally purchased a high end iMac (27" display, Intel Core i7 3.4GHz, Nvidia GeForce 680MX Graphics, 1TB Fusion drive) and expected the iMac to run games flawlessly. However, after a few days, I noticed that the CPU and GPU had shot up to a worrying 80°C whenever I ran power-hungry games, with a very loud hissing noise from the fan. After running games for about 10 minutes, the fan will stop hissing, causing the GPU and CPU to increase to 100°C. The iMac then fails and switches off unexpectedly without any warning. After analysing the Windows event logs, I received an event ID 41: The system has rebooted without cleanly shutting down first. This error could be caused if the system stopped responding, crashed, or lost power unexpectedly.
You must know that Boot Camp isn't compatible with Windows 8 and that Apple hasn't released drivers for Windows 8, so it can fail. Install Windows 7 inmediately until Apple launches updated drivers.
As it looks like the hard disk is damaged, I would take the Mac to an Apple Store. It's in warranty, so it should be repaired for free or you should receive a new one

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I had my imac since 2011 and never had a problem with it, until 1 month ago. It started to make a loud fan noise. I already reset the SMC, (http://support.apple.com/kb/HT3964) but I keep hearing it. Also checked in disc utility and everything is fine (not a disc problem).

I run Apple Hardware Test and gave me this:
4SNS/1/C0000008: TL0p-- 124
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I had a similar problem. Old mac pro and randomly the monitors would go black.
Replying to this incase anyone else has this problem…
Tried all the restarts under the sun, reset the board only to get temporary fix. It got to the point where the monitors would black out repeatedly after a few minutes of resetting.
My final solution (May not work for everyone): Remove the graphics card and check to see if the copper fins in the heat sink are "caked in dust". On my ATI card i can see this from the bottom end. I took the hoover and placed it at the opening and the bit of the hoover nozzle that stuck out I covered that with my finger for maximum suction, I repeated this process from the opposite side where the air exits, after a few seconds the suction was enough to clean out the heat sink and the fan started to spin with the power of the suction.
I have replaced the card and now my mac is running very quiet for the first time in years. On removing the graphics card I noticed the bay was very hot including the card. I'm guessing the card cuts out to protect itself from overheating.
Don't forget to wear an anti-static wristband or discharge yourself first. Using a hoover was a drastic last step. Don't think an air duster would solve the problem as well as suction.

Loud fan / overheating G5 - can anyone help?

Hi - My iMac was fine until I used Toast. After burning a couple of discs very quickly it kept turning itself off. I looked at the log, and it had been overheating. I haven't tried burning any more discs, but the machine is now very noisy, even when just turned on. It also turned itself off when I tried to ftp some files from one of my websites.
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optiical drive 1384
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resset smu http://support.apple.com/kb/HT1767
First time I tried it the computer turned itself straight off again after being turned on. I tried agtain, and it is on after 20 minutes, but still noisy. The figure for the CPU using iStat is still 3600 although the other figures have gone down a little.
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The G5 iMacs have had problems with the capacitors and the power supply, but since you have the iSight, it's no easy matter to open. I suggest you take it in to Apple and have them open it and check the caps on the logic board and the power supply. If the logic board needs replacing, it can be quite expensive and you'll have to decide whether it's economically justified.
Please let us know what happens,

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my laptop shut down unexpectedly. ( just before I had plugged an external hdd to find a photo, I never saw the hdd in finder)
it was dead, I left it for 30 hours, nothing. I left it a further 24 hour and the battery light showed it was charging and when I tried to start it, it started the fan (loud) beeped once, nothing on the screen .
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Try resetting the SMC. If that does nit help, take it in for diagnosis.
Barry

MBPRD 15" - Dead Pixels, Loud Fan, Overheating...

"Hello there!
Have been a devout user of your products since my early years! Never had an issue (dodgy disc drive here and there, but nothing to write home about!)
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Thanks
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Thanks for any help anybody can offer!

Sorry, only other users here and your problem appears to be a hardware issue we can't resolve.
https://locate.apple.com/country

Imac gets grey screen and fan runs hard

When I try to turn on my computer I get a grey screen with an apple and the fan runs like crazy. Sometimes I just get a grey box saying I need to reboot in several languages. Along with the fan running. Other times I get the grey box and then a bunch of text behind it with the fan running. I have tried to reinstall Leopard twice and get the same thing. Any ideas?
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Hi Jason - have you tried booting from your install disc and running Disk Utility?
1. Insert the Mac OS X Install disc that came with your computer, then restart the computer while holding the C key.
2. When your computer finishes starting up from the disc, choose Disk Utility from the Installer menu. (In Mac OS X 10.4 or later, you must select your language first.)
Important: Do not click Continue in the first screen of the Installer. If you do, you must restart from the disc again to access Disk Utility.
3. Click the First Aid tab.
4. Click the disclosure triangle to the left of the hard drive icon to display the names of your hard disk volumes and partitions.
5. Select your Mac OS X volume.
6. Click Repair. Disk Utility checks and repairs the disk.
If your drive has been repaired, boot from your internal and repair permissions.
You might also try resetting the PRAM

Very loud fan upon starting imac. Does anyone know how to fix?

My iMac has a VERY LOUD fan that turns on during start up and does not stoop. I tried to shut down and start up again. I also tried to unplug the machine overnight. Still happening.
Anyone have a solution?

This is a part of the larger MacBook Pro connectivity issue. There are several related threads dealing with the MBP's networking problems. If your unit is suffering from this type of difficulty, good luck ... (or a long ethernet cable)
(PS Everybody please make noise on this one so apple comes up with a solution.)
< Edited by Host >

Hoe can I securely recycle iMac with blank screen - should I remove the hard drive, and anything else?

My iMac died after 8 years - blank screen, loud fan noise, no way to erase personal info. To recycle should I remove hard drive, and anything else?

Removing the hard drive should suffice. Use Google to find takeapart instruction, using you iMac's processor description in the search.
At eight years old, it is probably a G4 (the "desk lamp" style with an articulated display arm and white hemispherical base). So the search string would be "iMac G4 takeapart." If it turns out to be some other processor, simply substitute that processor (G3 or G5) for "G4."
The HD may not be bad, so you could keep it and connect to a newer Mac to retrieve files using this handy and inexpensive gadget:
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Imac freezes on startup grey screen and really loud fans

My Imac G5 non intel 20" freezes on startup grey screen and really loud fans start and it won't boot. just have the logo on the grey screen.
I've tried resetting Pram - think that was the right thing to do?
I've tried disk utility, but it won't settle for me to choose the hard drive, it kind of sticks and keeps rotating the wheel.
any ideas anyone?
please help.

Lots of things you can try - first, try resetting the SMU. Next, boot from your install disc, go to Disk Utility and try to verify and repair your hard drive. If that doesn't work, try running the Apple Hardware Test on one of your install discs.
Also, depending on which model you have, you may be eligible for Apple's power supply or video and power issues.
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IMac 2007 20'' black screen and fan loud

Hi, I have a imac from 2007 and i got it from an other person that said to me that the problem was the rams, and i got the rams and the screen continues black and the fans loud.
Thank you.

Hello brunofig132,
Thank you for using Apple Support Communities.
I understand that your iMac is booting to a black screen and loud fans. The following article provides steps to troubleshoot the startup process for your iMac. It should give you an indication of what might be causing the problem.
Your Mac won't start up in Mac OS X (Mac OS X 10.3.9 or earlier) - Apple Support
Regards,
Jeff D.

Loud fans in sleep mode 20" G5 iMac Rev A, OS 10.4.11 New Info

This is more of a confirmation and heads up on a problem I encountered and solved to see if any of you have other ideas.
Several weeks ago I replaced the power supply bought from Mac Pro Online in my G5 iMac. When I put it to sleep I hadn't noticed anything odd at first because I'ld just walk away until one day I could here the fans going full blast. The screen was off as usual but the sleep mode light wasn't on while the fans were running. I waited about a minute until the fans returned to normal speed and the sleep mode light returned to its usual behavior only it seemed to be a lot brighter.
I awoke the iMac from sleep and all was fine. I put it back to sleep and the screen shut off as usual but the sleep mode lights wouldn't turn on. I waited about a minute and listened to make sure that the iMac hadn't shut down and then the fans started up full blast for about 30 seconds and then returned to normal and the sleep mode lights turned back on.
I shut the iMac down, disconnected all USB and ethernet cables and reset SMU using the unplug power cord, 10 second wait, replug holding down rear start button. Fixed it!
Swapping out USB devices I narrowed it down to a Kingston USB Multi-sized port memory care reader hub-part number: FCR-HS219/1. I tested and got repeated results described above reconnecting it and downloading some images and ejecting. Loud fans in sleep mode happened again.
Tried a MobileMate Memory Card Reader, downloaded images, ejected and no problems with sleep mode.
My question is what could've messed up the Kingston Card Reader? It was working fine before the power supply replacement.
Thanks,
Tim

There's no telling.
Only cause that came to mind is a lightning hit last week that sounded very close by where all it did was cause the lights in my home to blink. The computer didn't. However, this might have fried the Kingston card reader.
To give an idea of the resilience of the former power supply, about a year and half ago I had the back off with the iMac sitting upright on a towel on the table while I played a YouTube video to see if I could cool this thing down. Instead of cooling it I overheated it by blocking the vents to where suddenly the iMac just shutdown. I could detect a strong smell of melted plastic from the power supply.
Put the iMac back on its stand and restarted without a hitch and I've never had any problems until several weeks ago when it just started shutting down for no reason. It passed the LED light test as it still does now with the new power supply.
This is the first Mac out of three I've had since 1998 that allowed me to see odd behavior like this. I had to rely on my 2000 Pismo G3 PB to find a replacement PSU online. That thing never breaks.

IMac G5 keeps freezing/crashing. SMU reset resulted in a loud fan noise.

I have a refubished iMac G5 OS X 10.6.8 desktop that was purchased in Aug, 2006. Recently it has been either freezing, shutting down completely, or the display will just shut off multiple times per day 20+ times/day. I am not interested in purchasing the $49 help from Apple. Is it time for a new computer?
I've been attempting some troubleshooting:
I have plenty of RAM- we installed more memory about 8 months ago.
Temperature running at 40 degrees C
I reset the SMU but now am hearing a loud fan sound and there is air blowing out of the horizontal vent in back of the desktop- which does not typically happen. The computer has not crashed since I reset the SMU 20 minutes ago. I'm worried about the noise.
Also, it has been really hot where I live, with a heat index of 110 today and I don't have air conditioning. Current indoor air temp is about 86 degrees F.
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Not that this will cure it but it may help:
As old as your iMac is, have you cleaned out the dust? Dust buildup can lead to over heating issues. Remove any and all things plugged into it including the power cord, Remove the RAM access grille. Vacuum all openings starting with the RAM access area (air intake). Vacuum all ports and plugs, DVD slot and the opening across the top of the rear of the body. Blow compressed air through all your openings and vacuum again to remove any dust you loosend. Reinstall the RAM grille. Plug in the keyboard and mouse if not blue tooth. Insert power cord...
You are now in a perfect position to do a
SMC RESET
http://support.apple.com/kb/HT3964
Shut down the computer.
Unplug the computer's power cord and ALL peripherals.
Wait 15 seconds.
Attach the computers power cable.
Wait another 5 seconds and press the power button to turn on the computer.
It is the 5 second timing that initiates the reset.
Here is a link to a Widget to monitor your temps and other operations:
http://islayer.com/apps/istatpro/

Black Screen...loud fan noise

While online today, the power in our house went out. When the power came back on, I re-started my Mac. Black Screen and loud fan noise. I have turned my Mac off and on about 10 times. I've also unplugged. Still black screen and fan noise. Any suggestions?

rad_thundercat wrote:
I'm having this exact same issue.
I moved my iMac to another room, plugged it in and turned it on. Black screen and racing fans. No beeps. I've tried all the PRAM and SMC resets, still nothing.
Not the exact same issue. Please create your own thread. However please do the SMC reset at least 3x back to back. It is also possible you are not doing it correctly, please follow the directions in:https://discussions.apple.com/docs/DOC-3603

IMac G5 Garbled Screen / Loud Fan / Overheating

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