Already on it & interesting. You probably already know it but the 6HS5 or 6HV5
need the correct damper tube. See tube chart, tag on HV cage, or manual.
Last note is there is a VDR in the HV reg. Doug, DRH???? found a sub
& the story is here from abt 4 yrs ago. IIRC when they go reg is bad & there
is a bend & blob at the bottom of screen.
BTW I have a Zenith parts price list from 1978 & it has subs if you need any.
73 Zeno
LFOD !