Are the CTC5 HV supplies weak?

[trinescope]

I have my CTC5 Chandler up and running, but it just seems to have a weak HV supply; if you turn up the contrast/brightness the picture exhibits classic blooming. The HV supply drops down to about 15KV when that happens, pulled the plate cap of the 6BK4, still acts exactly the same. I have a new 6CB5, 3A3, and 1V2 in there, have not changed the 6AU4 damper since I don't have one on hand at the moment. I've heard reports that the CTC5 just has a weaker HV supply than the previous and later chassis, is this really so? Everything else seems fine except for this.