Saved my Macbook Pro from the trashcan.
20 - 30 minuten
My Macbook Pro mid 2012 didn't boot after a forced shutdown. I took it to maintenance and first, they said it was OK, but getting to the store it didn't boot again. Technician said it was a logic board failure. I mentioned the cable, but he said he already tested it.
I decided to browse some more and found many similar reports of faulty flat HDD cables. I decided to give Ifixit a try, and ordered the cable plus some tools for the job. The order came very fast for an international order. It was a matter of following the instructions at Ifixit's website, and the laptop was running again, back from the presumed dead.
I would say that Ifixit is a wonderful place not only for digging the parts you need, but to see the experiences of users and their issues solved. I wish I had a similar alternative in my country. I would suggest you dig a lot around the web and take with a grain of salt when a technician tells you your machine is gone. Specially when it is something as expensive as a laptop. Thank you, Ifixit!
Phillips #00 Screwdriver
MacBook Pro 13" Unibody (Mid 2012) Hard Drive Cable