Fred,
The vibrator appears old. It does not say positive or negative ground on the can. The can says:
Vokar quality brands
Replacement Vibrator
Universal NP42V 6-Volt
Vokar Vibrators- preferred by leading manufacturers of auto-radios
Super silent
higher output
sure starts
I would guess it is a mechanical type.
Shouldn't the transformer still have a voltage output on the P posts of the OZ4 tube
