Dear Richard,
I recently get the some problem with you. I got my Form1+ in Feb2015, and not yet consume 1L of resin. My first few small scale prints are perfect. One time I tried to print out a large scale model, my Form1+ starts to fail print until now. I still cannot get a perfect print. I have done what you have done.
- Change resin tray
- Clean resin tray
- Change resin color
- Re-orient the model during print out
- Make hollow of model and make solid of the same model
Nothings works so far.
You may find hint in this laser problem thread: Form1+ laser flare issues illustrated - pics and video - #12 by Ante_Vukorepa
You may be in the same problem as us.