I agree that. But 7854 and 7904 share the same CRT model (154-0644-05).
Why in my 7904 the exhibits more, more halo/flare effects than my 7854???
There's really a big difference between the two.
It's really the first time I've ever been disturbed by such an effect. In all my other oscilloscopes (465, 475, 7633, 7854) this effect is almost imperceptible.
As I stated previously, all voltages (high and low) are perfetly O.K. (I recapped ALL the SMPS capacitors with new Nichicon PWM grade ones).
Checking the -2960V catode supply (HV test point) with my Fluke H.V. probe I measured -2992V. It seems somewhat reasonable value to me, since Tek specs stated that this voltage should be -2960 V +/- 1%.
I'm unable to check H.V ripple because I don't know where to probe. The manual doesn't mention that check.