CTC 10 HV affected by brightness

[Turle]

Originally Posted by old_tv_nut

I presume the high voltage is normal when the screen is dark?

Have you replaced the tubes or only tested them? Tubes in the horizontal section can test good but be weak in actual use.

Yes when the screen is dark the voltage is normal, and I’ve substituted all the tubes for NOS ones with no change

[Turle]

I’m so lost I tried a few more things. None of the voltages or resistances look concerning. I checked the flyback it seems fine. Still no change