I have an old Lanzar 100-S MOSFET amp (probably from 1992 or 1993). It's a 2 channel amp, I think it's 50x2 at 4 ohms. Recently the left channel has been working only intermittently. I isolated the speaker that's wired to the left channel and I found that there is a tiny bit of music coming through when I turn up the volume. Any idea if this can be fixed?