Seems to me your hard drive is at the end of its life time. I now experienced the same and have to replace the HD. Apple built in drive CPR (I'am not familiar with the English name for this application) advised to reformat the hard drive, but this appeared already impossible.

@sikko Highly likely it can be fixed by somebody with the right skills and soldering rig. Fortunately I believe that socket is only for the little indicator LED on the front, so it’s likely not a mission-critical item. You can probably put it back together and ignore it. If I could pick one thing to break, that would be it ;)

Jeff Suovanen - 2 hours ago

Yes Jeff, I put the mini together yesterday and found that everything was working okay (with 32 GB of RAM) except for the LED light. Today I went to an electronics repair guy, who soldered the socket back in place. That made me happy again. He was professional and really nice guy and did not even charge me anything for this soldering of the LED socket! So fortunately all is fine again.

I noticed now there is a warning at Step 13. Very good! I don’t know if that warning was there yesterday; at least yesterday I did not notice it.

Unfortunately I &&^&@@ up on step 13.

I was afraid to pull on the LED wire and had no grip on the plug. The I tried to wedge with a knife from below and the whole socket including the plug came loose from the board.

I know now this was stupid! Probably I should have lifted on the wire itself, right?

Do you think the tiny connections from the socket can be soldered again by somebody more professional?