How long have you had this machine?
What kind of a ‘dot’ does the beam produce when you fire it on m1? Make sure you are in TEM0 resonance.
It looks to me that the lps is not maintaining voltage or the tube is failing.
Does it have a mA meter, if so, is it showing the proper current levels?
I doubt it’s the controller as it appears to be attempting to fire at the right time.
