I just aligned our laser here. This could be quite easy for the Argon laser
usedin BioRad MRC confocal scope. Select either of the two screws to start
with (I chose the bottom one), turn very slowly (don't exceed a couple of
degrees) while monitoring the anode current. Find the position that minimize
the current. Then adjust the other mirror to minimize the current. Repeat the
procedure a few more time to reach the final minimum value (which was 5.8 A
in our case). Don't be panic if you lose the laser, stay on the same screw
and turn back and forth until you get it back.
If realignment could not solve your problem, you may have to rebuild your
laser (We rebuilt ours at around 5000 hours) if the electronics works well.
But alignment is definitely the first thing to try.
Good luck.
Guoqiang