CTC 10 HV affected by brightness

[JohnCT]

Originally Posted by Turle

Been stuck on this for weeks. Initially I thought it was a focus problem, but The HV on my 10 drops to around 14kv whenever the brightness is up, and it jumps around depending on what’s on screen, I have no idea what could be causing this. I’ve pulled the cap off the regulator tube and it made no difference, the rest of the hv tubes are fine. the power supply seems to be working fine. I even tried a different CRT but it made no difference, does anyone know how I could fix this??

All help is appreciated. Thanks again

I know you said you tried all the tubes, and with that I'm assuming you replaced the HV rectifier in the cage?

I change hundres of those over the years for blooming - it's the number one cause of HV drop when beam current goes up. Try another rectifier.

Does the flyback get hot? A resistance check won't pick up a single shorted turn.

If not, providing the boost voltage as requested will give the group more to go on.

John