It wouldn't start if this were the case, however once it's running the effect on lasing shouldn't be too high.
As I said, try the shutter
If that's not it then lightly press on the side of the mirrors with an insulated prodder of some sort while it's running. This changes the position of the mirrors slightly so you can try and get a flash of light this way, then if you do you'll know that you need to align them. For this you need to push with more force so that the change stays. I'm not sure if you would need to slacken the locking nut or not ...