Elektrickery

I have fitted an Ultra 6000S transistor assist ignition. Starts and runs good but have a problem. I have ballast voltage at +coil (8.5v) upstream and downstream of the diode, when engine starts I have charging voltage (14v) at coil which sorta defeats the purpose of the ballast. Yes I have a "booster" wire from the solenoid but only energised when cranking. I can disconnect that when running but still have battery voltage at coil. Where the hell are those extra volts coming from? Diode tester says I have correct forward bias.
Anyone happen to have a wiring diagram? in English, found some in Japanese but they are images and google translate doesn't work.

Quite often the ballast feed is a resistive wire and if replaced with a piece of standard wire you get the full load of power regardless of what it should be.

Has the power feed to the coil been fiddled with at any time?

it's one of those old white ceramic doodads with some resistance wire wound through. If it burnt out then I would have no voltage. The only power going to the coil is from the ballast and the step down in volts look right to me. The same terminal feeds power to the ignition module, maybe when running it finds 12v somewhere and backfeeds? Tomorrow I will run a power wire direct to module bypassing the coil.
No doubt it has been fiddled with over the last 50 years, I reckon originally it disappeared into the harness and through the firewall, done a couple of laps under the dash then reappeared near the coil. I have a new lead with new connections straight from the ballast to the coil now.