[Penthode]

Yes I anticipated you might run into this. I would be inclined to remove the slug and use it on the original transformer. That is if you did not damage the original transformer when trying to remove the broken slug.

To loosen and remove the slug, you might try first a drop of mineral spririts to dissolve the wax.

A further solution which I have done on these sets is to remove the transformer and disassemble it. I use a heat gun gently on the tube holding the slug and heat it until the slug moves. I remove the slug, checheck the tube and ensure the slug moves with sufficient friction to hold it in place but loose enough to adjust.

Try the mineral spirits (turpentine) first. Add a drop and leave it a few minutes and then try to adjust.

The other slugs on the other transformers I assume are near where they originally were and can move enough for the touch up adjustment?

Remember, there is nothing magic about these transformers. I have replaced and made many coils and transformers for various sets. I have successfully remade the quadrature coil used in early Zenith color sets which are prone to going brittle and snapping. I have even reused the original wire failing to have on hand the correct gauge wire. It is just logic and perseverence.