My iMac has recently been turning itself off whilst in use but over the last day or so the screen has become unreadable. It looks like its covered with a net curtain. The programs run OK in the background but you can't see them to do any work. When restarting the Mac it makes a lound electronic howl before opening. Whereas I could get a proper screen previously it is always distorted now. It was suggested that the video card on the logic board has failed which means a repair of c.£650 which I cannot afford (or to buy a new Mac). The serial number does not apply to one of Apple's known faults unfortunately. Any ideas? Apple have not yet had a look at the machine.
I will try to give you a troubleshooting if you haven't done so.
first you could try is a PRAM reset, that might help to reset the paths of the logic board with internal components.
If that does not work try to reset SMC/PMU (power Management Unit) to see if that helps.
http://support.apple.com/kb/HT1894 (article with PMU instructions)
If that does not work and you want to know the issue, try to boot in verbose mode:
http://support.apple.com/kb/HT1492 ( this is the article in apple tech support that explains how to do so.)
When you do that,(in case you can see the log) it will tell you what the machine does while booting.
Try connecting to another screen too to see if it is the screen.
Let me know if this helped, if not I can try to give you a workaround.
- If you need clarification, ask it in the comment box above.
- Better answers use proper spelling and grammar.
- Provide details, support with references or personal experience.
Tell us some more! Your answer needs to include more details to help people.You can't post answers that contain an email address.Please enter a valid email address.The email address entered is already associated to an account.Login to postPlease use English characters only.
Tip: The max point reward for answering a question is 15.
The first thing I would do is boot up in safe mode see http://support.apple.com/kb/ht1455 this will boot the imac up without extensions on that includes video extensions which could be the source of the problem. See if the screen works after this, if it does it could indicate that the either video card is not operating properly or one of the drivers isn't. If you then search on google for your model of card and see if this is a known problem and you could find a work round. If it boots up as you have described it in your email it's a possiblity that the card is no longer functional and it will be expensive to repair.
It appears that your power supply is good, the startup chime says that the system board has passed self diagnostics. If you have a black screen then the problem is either the video card or the screen itself. Unfortunately it is very difficult to tell which one. You might try to use an external monitor. If it works, then the problem is with the LCD. To use an external monitor you need a Mini-DVI to VGA adapter, or a Mini-DVI to DVI adapter if
your display will use a DVI connection. Either adapter is available at
any Apple retailer. The connector on the back of your Imac is next to
the ethernet connector, and should be the last in the row.
The iMac G5 and iMac G5 (Ambient Light Sensor) computers have a video out port located on the back of the computer, which will mirror video. Video mirroring means you can see the same image that is on the iMac G5's flat-panel display on an external monitor, television, or projector. Using the video out port, you can mirror video with a compatible VGA display using the Apple VGA Display Adapter. You can also use the video mirroring feature with a television or projector that has S-video or composite video connectors when you use the Apple Video Adapter. Both the Apple VGA Display Adapter (M8639G/A) and the Apple Video Adapter (M9109G/A) are available separately, and are needed if you want to use your iMac with a VGA monitor cable, S-video cable, or composite video cable. The video mirroring feature is "plug and play". Simply connect a VGA display, television, or projector to the appropriate adapter (see above), then connect the adapter to the video out port located on the back of the computer. When you connect the adapter to the computer, the screen may refresh momentarily as the computer prepares itself for the new video output. The computer tries to match the resolution of the built-in and external display. If there is no match, the computer changes both screen resolutions and may black out areas on the built-in display in order to match the capabilities of the external display. Important: To ensure that your iMac G5 automatically detects the external display or projector, be sure you plug the adapter into the external display or projector before you plug it into the iMac G5. You can switch resolutions and frequencies for both the iMac G5 flat-panel display and the external display, television, or projector using Displays preferences. Want to watch a DVD movie disc on a television that's connected to your iMac G5? Select a 720 x 480 NTSC (in the United States) or 720 x 576 PAL (in Europe and other regions) resolution in Displays preferences. Tip: Because of the display limitations of most televisions, the images displayed on a television screen are usually not as high quality as those on the built-in display or an external monitor.
I have one doing exactly this at the moment. It had gone to sleep and the fans were going like crazy.
I think it is a Motherboard failure (it happened with many G5 iMacs), this one has been replaced once already, and I can't actually get it to install anything.
I'm taking it apart tomorrow to see what I can find inside. If I fond anything I'll let you know.
Hello, Sorry to hear you are having troubles,
Is this a 17” iMac G5, if it is, and I think it is, unfortunately, this iMac model was generation 1 of the all in one flat screen design and it's a bit of a Lemon... The hard Drive overheats the video card and the power supply. With time, these 2 elements burn out.
What you have sounds like the power supply.
it's a $300 repair, but, it might not be a good investment for you, the new power supply won't last much more than the first one and your video chip won't last much longer....
Best put the money and put it towards a new machine.
Sorry bout that.
Mine is doing something very similar now. I managed to do the Apple Hardware test and it came up with the Error Code 2 FAN/5/7: Hard Drive. This leads me to believe that the problem is the fan by the hard drive. Your problem may be the same thing. If so, it's just a matter of finding the part and the installation instructions (on the Apple web site).
Try the Apple Hardware Test from the Mac Os Software that came with the computer. You install Disc 3 and shut down the computer. Then turn it on and right away press C on your computer. This action will take you to the Hardware test. Press one of the buttons that does the test and see what results you get.
If you get the same error code you might want to check out welovemacs.com for the fan.