7904 excessive shadow/flare

unclebanjoman
 

Hi,
I've just repaired a 7904. Usual problem, SMPS not working.
Then I've checked all voltages, HV voltages, etc.. all it's fine, very good.
Just some adjustments to Z board, focus and so on.
The scope is in very good conditions, the trace is well defined, bright and sharp.

But there is an annoying problem that I don't think is normal.

It is the usual shadow / halo / flare effect but while in my two 7854s and 465s that already own this effect only manifests itself with somewhat high brightness, in this particular 7904 with low/normal brightness the halo/flare effect it is already visible and definitely annoying.
To give an idea I took a picture that you can see at

https://groups.io/g/TekScopes/album?id=90746

I reiterate that the photo was taken with the intensity controls were set for a normal brightness even if in the photo it seems that the brightness is too high.

I've compared side-by-side my 7904 with my 7854 (they should use the same tube model) :while the 7854 the flare/halo effect is unnoticeable, the 7904 is definitely visible already with moderate brightness.

I'm puzzled.
Could it be the crt damaged by some mechanical shock?
What do you think about it?

Thanks,
Max

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