So last October my K40 died in the middle of an engraving, at first I thought it was the power supply. So I replaced it and still no luck, so I put the old LPS back in, then replaced the tube with one from LO.
That worked I was up and running.
I have always engraved from 28% to 38% based on speed and material, sometimes going as high as 42% when I wanted a deep engraving. the LPS would squeal if I tried to do anything below 25%.
Two days ago, I engraved a painted tile, it got really dark 3/4 down from the top so it was not burning away enough paint. I know my mirrors were aligned so I thought, I should swap out the old LPS with the new one I bought in October.
WOW! I just engraved at 21% and it went deep (MDF), I then cut 1/8 mdf at 8 mm/sec in 1 pass, two days prior I did the exact same job in the exact same location. Which cut the same MDF in 3 passes at 38%. So it seems like my LPS was a little weak from the start.
I did purchase an analog meter that I will install when I map out my control panel.