My 14 year old Sony STR-DE875 surround receiver was starting to click a bit to much. And lossing sound in the back channels. I opened it and this video shows how the soldering was before I fixed it. No wonder its behavior changed when it was warm og cold ;-)
Now it plays again - and hopefully for the next 14 years or until I have to change to a receiver with HDMI 4K UHD ;-)