#1
K, so one of my geets is a SDGr 6-string bass guitar, its cheap but it plays good... usually,

Lately theres been a problem with what I think are the pick-ups, when I play for anymore than 10 or 15 minutes with it plugged in, the signal starts to fade and become quiet and/or distorted.

Now, its not the chord or the amp, those are out of the question as I've tested many, so I need some help, and by the way I'm incompetant in terms of guitar mechanics so if the answer seems obvious then have mercy.
#2
if it's an active bass you will find a 9 volt in the back, try replacing it
#3
I had the same problem, and was told to replace the battery. it worked.