My Lexel also have a 3 phase 208V plug but can be wired to a single 230V phase. My Spectra Physics supposedly use the same trick but I haven't verified that.
You just unverfied it.
Lexel supplies have a buck boost transformer in the front end.
If its a three phase Lexel and you hook it to single phase, your going to blow a couple of 60 Dollar fuses in the PSU. If its a single phase Lexel, and they do exist, ie model 75, model 85, model 88, it can run off any two phase leads in the three phase, but the transformers (2) must be retapped correctly via Lexel tap chart or you will hose the cathode and passbank.
SP 265 can only run off single phase for a few minutes before the main inductor in the PSU blows. SP265s modded for single phase have a much larger inductor that would have six times the steel in it. You'd also need to have to beef up the filter caps. See, the rippled current in rectified three phase is 360 hz, vs 120 hz for single phase. Higher rippled frequency allows for smaller filter components. So to drop to single phase, you really have to redo the filters.
Some other of SP''s more modern supplies ie Spinaker, 2016, can run dual mode, some times, depending on the software.