Dyna Bass equalizer

[DynaBMan]

The equalizer on my Peavey Dyna Bass is not working. All other controls work fine, but when I flip the switch down to turn on the equalizer, everything stops working. The battery had ran down a few weeks ago and when I went to change it out, I noticed one of the wires in the battery connection had came free of the circuit board. This has happened before and a friend of mine corrected it by soldering it back in place. I did the same thing this time, but the equalizer still does not work. I have taken it to a local music store whose owner has a lot of experience if repair, but he was unable to determine what the problem was. He suggested I call Peavey because there are a lot of electronic parts inside the bass that are only made by Peavey. He said he could install the part if they could tell me what the problem was. I realize diagnosing something like this, without having the guitar in hand, would be almost impossible, but I was wondering if anyone here new of a common problem with the Dyna Bass that I could inspect for and check myself. I have never had a problem with the guitar, in about 17 years of playing it, but it just doesn't have the same punch that I like, without the equalizer. Any ideas or suggestions would be appreciated.