CTC 10 HV affected by brightness

[timmy]

Seems like the hv is not regulating or responding to the load.

[old_tv_nut]

Originally Posted by timmy

Seems like the hv is not regulating or responding to the load.

No, if it was not regulating, high voltage would go too high with a dark screen. The regulator is a shunt regulator, which means it draws more current when the CRT draws less, to keep the high voltage constant by creating a constant total load. In this case, high voltage never tends too high and therefore the regulator never draws current. This gives the symptom that disconnecting the regulator cap makes no difference.