Hi Guys, My friend gave me his bass (mentioned in title) for some setup and soldering. He had some problems with the original preamp and EQ. The only thing I have found is quite similar diagram for SR600 from the mid 90's, but the main difference is the amount of cables coming out from pickups. The diagram shows only white and black (which is quite obvious what they are for) and 886 has four cables (bare, white, black and red). Are they active or what? I assume that this is a power supply circuit for them. Anyway, following my thoughts I soldered them like active pu's and the bass plays kinda wierd. I mean too quiet (which was the main problem earlier so I didn't fix the issue the treble pot brings no difference when you dialing it and bass pot make the signal stronger or weaker (like a second stage of a preamp ) If you have any knowledge I would help me a lot. I know that it would be easier to replace the whole thing but I would like to keep it original. Take care!!