Wow, wow, wow!! Grahame, I think if you are varying the grid current well within the design range and you see focus vary significantly enough to notice, you have a PSU problem.
Either you aren't supplying the right voltage to the anode, the deflection plates are not at the right potential (in many tubes, X and Y plates should be at slightly different potentials w.r.t. cathode due to their placement along the neck of the tube), or your PSU is not regulating well (not able to supply enough current). I would measure all the voltages while you vary the grid bias and see if anything changes significantly. (Of course, even professional oscilloscopes and X-Y monitors exhibit this focus change to some degree, at extreme intensities.) (My <a href="http://oscilloclock.com/protoype ">Prototype</a> has this problem in a big way, due to the super poor job I did winding my own transformer! Aaron -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to [email protected]. To unsubscribe from this group, send email to [email protected]. To view this discussion on the web, visit https://groups.google.com/d/msg/neonixie-l/-/duFBNm0X20cJ. For more options, visit https://groups.google.com/groups/opt_out.
