Went to play my Deluxe Strat on the weekend and the humbucker was only putting out about 1/2 volume compared to the two single coils (I tried all S1 and push/push modes as well). Long story short it ended up being a funky pot. It was smooth, and wasn't scratchy but I guess there was some "gunk" in there that was restricting the signal? The more I worked the pot the better it got but ultimately I had to pull the pickguard and spray a few shots of DeOxit into the pot to completely fix it (for now?). Has anyone seen this before? I've heard of pots getting scratchy as they get old but this was different.