Macbook Pro Screen: Will not turn on, yet can still connect through HDMI cord to TV.

Hi mjwindett!

I have an article for you that can help you troubleshoot this issue and can help you rule out some possibilities. The article can be found right here:

Apple computers: Troubleshooting issues with video on internal or external displays

http://support.apple.com/kb/ht1573

The specific part of the article you will want to turn your attention to can be found here:

No video or no signal, image distortion, "snow," or flickering

Check connections

When using an external display be sure to check the following:

1. If you're using an Apple notebook, confirm the AC power cable or adapter is securely connected to the computer and the cable providing power to the display is also secure. It is always good to have your notebook connected to AC power when an external display is in use.
2. Confirm display adapters are fully seated in their respective connections and that they are supported models and for the computer and display. Refer to these articles to assist you with adapter compatibility and further configuration information:
   • Monitor and Display Adapter Table
   • About Mini DisplayPort to HDMI adapters
   • Apple Mini DisplayPort adapters: Frequently asked questions (FAQ)
   • Thunderbolt ports and displays: Frequently asked questions (FAQ)
3. Remove all display cable extenders, KVM switches, or other like devices and retest to determine if the issue is resolved.
4. Try unplugging the video adapter or cable and then plug it back in.
5. If more than one video adapter is in use (or "daisy-chained"), troubleshoot by using only one adapter.

   Example: A mini DisplayPort to DVI adapter connected to a DVI to HDMI adapter is an unsupported configuration because there is a series of adapters in use.

6. If available, try using a different display and or adapter (or use a different connector by using DVI instead of VGA, for instance).

Reset the system
You can reset the Mac's parameter RAM and SMC.Reset the resolutionStart by resetting the Mac's parameter RAM. If the display does not come up, was previously set to an unsupported resolution, and still results in no video:

1. Start up in Safe Mode.
2. From the Apple () menu, choose System Preferences.
3. Choose Displaysfrom the View menu to open the preferences pane.
4. Select any resolution and refresh rate that your display supports.
5. Restart your computer.

Thanks for coming to the Apple Support Communities!

Regards,

Braden

The odds are that you are correct. If the MBP appears tp be operating normally but the display is dark and an attached monitor display is also dark, the the GPU is the prime suspect. Make an appointment at an Apple store genius bar and have it definitively diagnosed. It is not a inexpensive repair. The entire logic board will have to be replaced if the GPU has failed.

Ciao.

Consider yourself very fortunate. I have seen logic board replacements to be in the $600 to $800 range and display replacements to be priced up to $600. Trust me, you have no cause for complaint. For $280, I would willing do that any day.

Good luck.

Ciao.