Help: Stingray doesn't play

I have problem with my Stingray, manufactured in 1991, 2 band EQ. Sudenlly it stoped play. At home I’m playing over external sound card, when I roll gain and master to maximum, I can hear the bass, but it seems that bass control doesn’t work too. I changed battery but nothing changed.
So I made an audio probe and went over the circuit, signal form pick up is strong and clean, signal is OK until it reaches OP Amp, on input to OP amp signal is OK, but on output from OP Amp signal is weak, weaker then on input. So, I decided to change OP amp but nothing changed (I used TL072 instead of LM4250, but according to datasheet pin inputs should be same) . Does anybody knows what to do or what is a problem?

Thank you for answers