I use 2 thunderbolt displays with Mac Mini, daisy chaining the second one from the first display. I have been using these displays since 2011 and last month in a gap of 15 days both the cables started exhibiting unreliable connectivity. I ordered a pair of new cables and eventually after a month of waiting, I finally got them yesterday.
Opened display #1 using this guide (which is a life saver) and that roughly took me over an hour to tear it down. I additionally opened out each of the 3 speakers and brushed off the 8 years of dust accumulated on them. Blow cleaned the fan which had tons of dust caught inside.
This guide is quite well drafted with each step very illustratively put together. Not just my display is back in action, but also the audio volume of the display has doubled up :) I also cleaned off the soot developed behind the front glass and now its like a entire refreshed display.
Kudos to the author for this article!
Will work on the display #2 sometime soon.