Zenith Chromacolor Neck Setup

[Electronic M]

There's a solid ring of metal inside the neck closer to the glass than the rest of the gun. That ring (convergence pole piece) is about as deep front to back as the convergence yoke... position the convergence yoke over it.

Worst case scenario where you can't get a red spot on screen with the deflection yoke against the convergence yoke pull both straight back without rotating them and set the purity and then readjust the convergence.