Help Needed Vestax PMCPro-05 II

so i bought a vestax mixer a while back, and the problem with it (as ive read alot of mixers too) is that there is a horrendous buzzing through the headphone port. the rest of the mixer sounds perfect, and i can hear music through the headphone port, its just that there is a constant buzzing or humming that never stops. it gets louder as i turn the volume up, but doesn't go away when i turn it all the way down.

anyone know how to fix it? its driving me insane! i cant even stand plugging in my headphones anymore.