Answer to "How do I unlock a disabled iPhone 6 without itunes?"If the iPhone is disabled because the passcode has been lost, the iPhone needs to be restored. If you setup your iPhone security such that it will auto-erase after 10 failed passcode attempts, you could keep entering passcodes until the iPhone erases itself. If you didn't setup that security option, here is another option. If your Apple ID is still logged into the iPhone and the iPhone has an active internet connection, log into https://www.icloud.com/#find and erase the iPhone. You would then be able to restore from an iCloud backup (if you have one) or setup the iPhone as new. If erasing the iPhone via iClould is not an option, you will need iTunes. Since you are asking for a solution without iTunes, I won't go into that solution; however, here is a link that gives you that detail. https://support.apple.com/en-us/HT201263 Without iTunes, I would recommend bringing the iPhone to an Apple Store where they would be able to restore the iPhone for you. Good luck!
Answer to "No output audio on MBP Retina, only startup chime"If there is no red light inside your headphone jack, I would check System Preferences / Sounds / Output to make sure Internal Speakers are selected. If there is a red light inside your headphone jack, it means your Mac thinks an audio plug is inserted. I've read of people wiggling a headphone plug or a toothpick inside to reset the internal switch. If the switch itself is damaged, the audio port integrated into the main logic board; and the whole board would need to be replaced. It's an expensive repair. MacBook Pro 13" Retina Display Mid 2014 Logic Board Replacement Good luck.
Answer to "Replaced Screen, No Backlight, Swapped Back, Still no Backlight"It's been forever since I repaired one of those, but I believe it's the inverter cable that providers the power that lights up the screen. It's Step 14 in this guide: MacBook Pro 15" Core 2 Duo Models A1226 and A1260 Display Assembly Replacement I would recommend unplugging and replugging that connection and make sure its cable isn't being pinched. There's also a chance that 1. the replacement monitor isn't working properly or 2. the port on the main logic board is damaged. Good luck.