@luddoro you do want to go ahead and disassemble your headphone right to the speakers (drivers) and check the logic board for corrosion on the components as well as check the wires for corrosion and fraying. I suggest that you also replace the battery since that can cause weird crackling as well as other issues. As for the sliders, we really would need to see what the broken ones look like. There might be a more permanent fix for it or your may have to purchase replacements. You could always check places like ebay.com for a pair from a broken headset or try to find somebody to 3D print those for you. It's a fairly expensive headphone so parts will be expensive as well. This guide shows you how to repalce the battery and how to get into your headphones [guide|147364]
[guide|21499]