Hi guys, I need some help with my ES330 tribute. I have P90's installed with B500k tone pots and .22 caps. The pots are cheap Chinese ones. The problem is that the tone pots on both pickups don't really change the tone until the pot is almost fully rolled back ( '0' position ). I have tried both modern and vintage wiring styles too.

Question is: Is it a pot, wiring or cap problem? What are the possible solutions?

Your infinite knowledge and suggestions are appreciated.