serviced. There seems to be a common issue with these where the balance control is temperamental and some people bypass them entirely since most users would tend to keep it centered anyhow. We did a compromise where we simply solder bridged 2 of the pot terminals (easily reversible if someone want to replace the pot instead), so now stereo sound is even and stable as long as knob centered, and when turned all the way to one side or the other it will mute that channel but no balance taper.