No sound coming out when you plug your cartridge in to the tone arm on your turntable?
Only hearing one side?
Poor calibration in Serato/Traktor?
Don’t blow into the tone arms, please. The little bit of saliva does not help any humidity situation that may already exist.
Could be oxidation. This video is great… I don’t have and have never used a Dremel doing this but you get the idea…