Ok well I just changed my picguard and to do so i have to move the picups a little bit to fit. while they were out i tried to re-sheild the control cavity and i used some "exhaust tape" its basically aluminum tape all over the cavity. anyway now when i plug in my bass i get nothing but a crazy loud hum and i cant even hear the strings when played over the hum. any idea's? possible problems i have thought of the new shielding? pickup placement? (can they be backwards or upside down or somthing?) maybe a loose wire? oh and its on a cheap pbass copy that i am just playing with for learning how to work on my own basses. thanks again.