iMac Self Upgrade Disaster!
I have a 27" iMac (mid-2010 model) which I was not able to upgrade to the new Sierra MacOS because the installer stated my hard drive was about to fail (from the S.M.A.R.T. diagnosis). So, I decided to replace the existing hard drive with a faster Solid State Drive (SDD) purchased from OWC (along with their upgrade/tool kit). Following the installation video on the OWC site as well as the ifixit.com site, everything was moving along nicely up to when I needed to reconnect the LCD video cable to the logic board. When I inserted the cable end into the connector and pushed down, the connector on the logic board broke off! This must be most horribly flimsy connection I've ever seen on a computer board. Very, very easy to damage the connector when removing or inserting the video cable.
At this point, since my 2010 iMac is older than 5 years old (Apple considers it "vintage"), the Apple store won't repair it as Apple no longer makes replacement logic boards. I called several local 3rd party Apple Authorized Repair Centers, but none of them were willing to repair the broken connector or replace the logic board. My only option at this point, is to either send out the logic board to a company outside my state to repair the connector for around $250 US, or buy a used logic board off of eBay for around the same price, or scrap my iMac and buy a new one. Since I'm worried I may do a repeat and break off the connector again when I try to re-insert the video cable, I don't think I'll go down the path of getting a used replacement logic board. So it seems the only option is to get a new iMac which is a $2,000+ expense (ouch!).
In hindsight, what I should have done was NOT remove the video connector cable from the logic board. Instead, angle the screen out by 45 degrees and use masking tape on the sides of the iMac to suspend the LCD screen out while I replace the hard drive. There seems to be enough room to do so without removing the LCD screen entirely from the iMac chassis. Or even better, have a local Apple repair shop swap out the hard drive and pay them to avoid making the same mistake I did.
I just thought I'd share my experience for those thinking of doing some self upgrades on their older iMacs. It's possible, but be very, very careful with that stinking LCD video connector on the logic board!