Cracked screen, boot from USB, external monitor not recognized...

[sarcnelson]

So, here's the situation:

I have an early 2009 17" Macbook Pro. The screen has sadly been broken for some time, so the laptop stays at home with an external monitor constantly plugged in and I use it only in clamshell mode.

I wanted to do a clean install of the OS, so I backed everything up, created a bootable USB and went into settings to have the laptop boot from USB. Shut down the laptop, booted from USB...and the external monitor remains blank. The actual laptop screen is lit up - I can't read anything on it though so I don't know what is displaying - but the external monitor turns off and says that it doesn't recognize my laptop anymore.

I've tried starting and restarting, but the external monitor is never recognized. I have a USB mouse and keyboard plugged in, but those don't seem to wake up the external monitor at all. I tried unplugging and plugging back in the external monitor, with no luck. I've tried several keyboard commands to try and wake up the external monitor: fn+f1, cmd+fn+f1, fn+f7, fn+f2....all with no luck.

I've done some research online to find solutions, and the only suggestion I've found is to plug in an external mouse/keyboard and use those to "wake up" the monitor. I've tried that, but without any luck. Does anyone have any other ideas?

Thank you for any suggestions!

 

[treekram]

What OS are you trying to install? If it's Sierra, the 2009 MBP isn't officially supported.

 

[sarcnelson]

What OS are you trying to install? If it's Sierra, the 2009 MBP isn't officially supported.

Yes, I understand that, but the OS that I'm trying to install isn't really the issue. Regardless of which OS I'm trying to install, I've still been unable to boot from USB and still see the screen through the external monitor. I have tried with a USB formatted for Sierra as well as El Capitan, and I experience the problem regardless. It just won't allow me to see the external monitor whenever I boot from USB.

 

[treekram]

This is from 2007, but it may apply to your MBP:

"The trick is to close the top of the computer as soon as you power on the laptop in order to cause the Apple drivers to default to the external monitor. This method works every time but only after too much time spent with trial and error figuring it out. "
http://blogbarley.blogspot.com/2007/11/leopard-105-on-macbook-with-cracked.html

If this doesn't work, make sure your USB installer can boot and works (see if you get to the initial installation window) by trying it in another Mac, if possible. There is nothing in your post which indicates that you have tested to make sure you have a viable bootable installer.

If you are using a USB3 flash drive, you might want to try a USB2 flash drive.

You don't have to use a bootable USB flash drive installer to do a clean install. If you can boot from an external HDD and the external monitor works, you can install from that. If your backup is a bootable clone, you can try that, otherwise you'd have to create the bootable clone. If this works and the external monitor does not go on at the end of the installation process, you'd have to guess when the installation process is done and then reboot at that point. If it were me, I wouldn't use the bootable clone if that were the only backup - there should be two viable backups at any point of this process.

If all of this doesn't work, at this point, I would just remove the internal drive, get another Mac and use it to install the OS to the drive and place it back in the MBP.