My intel 17" mac has an almost black screen. It is too dark to see the mouse pointer but I can tell it is on. When I push the power button to force a shut down, the screen brightens for just a second and I can see a normal looking desktop before it shuts down. I have zapped the pram. I have hooked up an external monitor and it shows the desktop background but mirroring is not on so I can not use it to navigate. Any ideas?
Screen goes very dim
- Thread starter jim6856
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- Your Mac's Specs
- 2017 27" iMac, 10.5" iPad Pro, iPhone 8, iPhone 11, iPhone 12 Mini, Numerous iPods, Monterey
If the external monitor shows a normal raster (video) with correct brightness, we can assume the GPU in your iMac is working OK. It also means your logic board is probably OK. That leaves us with the internal display of your iMac.
The symptom you describe may be a failing backlight (the CCFL which lights the screen) or it could be a defective inverter. Of the two, I would be more inclined to suspect the backlight. The inverter is a do it yourself replacement but does require care and skill. However, since replacing the backlight in the display, especially an iMac, is a daunting and difficult job, it's usually better to replace the entire display.
And there may be other reasons your display is not functioning correctly....
If your iMac is still under warranty, it would be best to have it looked at by Apple. If not, then you have a decision to make on how to go about repairing it.
Regards.
The symptom you describe may be a failing backlight (the CCFL which lights the screen) or it could be a defective inverter. Of the two, I would be more inclined to suspect the backlight. The inverter is a do it yourself replacement but does require care and skill. However, since replacing the backlight in the display, especially an iMac, is a daunting and difficult job, it's usually better to replace the entire display.
And there may be other reasons your display is not functioning correctly....
If your iMac is still under warranty, it would be best to have it looked at by Apple. If not, then you have a decision to make on how to go about repairing it.
Regards.
Thank you for the info.
I have taken the cover off and pushed in all the connections related to the inverter board.
I started it up again and no problem with the screen. It is bright and clear.
We will see if it stays that way.
I have taken the cover off and pushed in all the connections related to the inverter board.
I started it up again and no problem with the screen. It is bright and clear.
We will see if it stays that way.
- Joined
- Jan 23, 2008
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- Your Mac's Specs
- 2017 27" iMac, 10.5" iPad Pro, iPhone 8, iPhone 11, iPhone 12 Mini, Numerous iPods, Monterey
Sounds like you may have lucked out. Let's hope it was just a loose connection from the inverter. Keep us posted.
Regards.
Regards.
It might have also been the act of disconnecting the power that fixed your problem, rather than wiggling the internal connections. I believe the power management unit (now called the SMC) is reset by unplugging all connections for a few minutes.
If it happens again, you could also try booting off the Mac OS X disk and see if it's software-related. (If it is, the screen should be bright when booting off the OS install disk.)
If it happens again, you could also try booting off the Mac OS X disk and see if it's software-related. (If it is, the screen should be bright when booting off the OS install disk.)
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