Hello,
Which mask aligner are you using. I have been using Suss Microteks MA 1006
manual mask aligner.  Sometimes the fuse of my mask aligner trips off. But
this is only if I have put the mask aligner first and then the lamp.
The manufacturer suggested me to put the lamp on first and then the mask
aligner. Do you also do it the same way. If not then just follow this
routine and you might not get the problem back.
Sudesh