just like to share my experience with adjusting the AF beam that was hopeless
aiming outside of the lens Centre AF point.
the way to open up YN-622 radio trigger has been explained nicely here.
The thing that caught me was the 5th short screw that was covered with
Without this work done here by Cliveboy, i wouldn't have gotten it opened.
Once the 5th screw is released, the covers come off nicely.
The laser is held by 2 small screws and has a bottom plastic support.
Its this plastic support that comes handy when you need to adjust the laser.
I inserted something springy below this plastic support so that it pushes the laser up.
You will need to loosen the 2 screws holding the laser first.
THEN, using this springy support, you can then very slowly adjust the laser
by tightening the 2 screws.
This will raise or lower the laser by just that tiny bit.
You will need to go back and forth testing your lens at various distance
to see how much to tighten or loosen.
Dont worry about the case screws cause as long as you dont use too much force,
they come off and go in rather easily.
MAKE sure you use the correct size phillips screw driver. Think its the smallest size.