Update.
As I mentioned earlier, I opened a ticket with FormLabs support and they too suggested that I clean the mirrors again. SO this evening I got to it. Cleaned the galvo mirrors, the larger deflecting mirror as well as the main mirror. Downloaded the Butterfly test print, regenerated the supports at 50nm, and pressed print.
2 hours later I got this:
So obviously, it’s not the optics, it’s something else.
Something just occurred to me. A while back, I had to replace the power supply. At that time I couldn’t find a 24V @ 2.5A, but I had a 20V @ 4.5A, tried it and in worked. In fact it’s been working for the last 8 months or so, so I had forgotten about it.
So could the power supply have something to do with this problem?
Assuming the power draw is not constant, the highest draw should be when printing at 100 or 200nm as the laser is at a higher output. But then again, the power supply I’m using is 90W, whereas the original is 60W. So it’s not the power/current draw, but could it be the voltage?