Chromacolor II Instant on

[Jon1967us]

I was surprised, as it appears my 1974 19” CCII has instant on. I was unaware these sets had it. With the back removed and the lights off, the CRT filaments are clearly lit when the set is turned off.

Did all CCs have this feature? I’m assuming they phased this out?
What voltage is applied to the filaments?

I have a switch on the AC outlet, but it may be good to do a mod to disable it.