Chosen Solution
I bought a second hand MacBook Pro, there are 6 keys that don’t work: Q, 1 and lower brightness and backspace, volume up and volume down (I’ve grouped them in threes because of their very close proximity to each other). I’ve reseated the keyboard connector on the logic board and even cleaned the contacts but no joy. There is no noticeable liquid damage I found whilst inside the MacBook and the actual keys seem perfectly in order. I was just wondering given the two sets of three unworking keys if it’s worth replacing the keyboard entirely or likely an issue somewhere else?
Sorry there is little you can do here to fix these keys discreetly! Keyboards are a bunch of mechanical switches which over time can just wear out! In your case there is some junk which has gotten onto the keyboard backplane which routes the discreet keys electrical connections into what the system can accept as an input. So you have two paths here either replacing the full uppercase while being more expensive is the quicker and easier way MacBook Pro 15" Retina (Mid 2012-Early 2013) Upper Case Assembly or replacing the discreet keyboard which is much harder but cheaper! MacBook Pro 15" Retina (Mid 2012-Mid 2015) Keyboard For either you’ll need to follow this guide MacBook Pro 15" Retina Display Mid 2012 Upper Case Assembly Replacement then removing the keyboard backlight and then you will need to fight through all of the 50+ screws (some have rivets as well). Just consider your skills, the value of your time vs costs!
