If you are confident, you can swap the capsule to the other mic and see if the problem follows the capsule. Otherwise have a
mic tech do it. handling capsules can be risky and expensive if you lack the experience.
nevertheless this is a lot of work to test a capsule, but its better than paying a tech for $$$$$$ to tell you if you can confirm it yourself.
If it is the capsule you can save a few $$$$ on buying a replacement direct from AKG and install it on your own. I believe the teflon transducer is the one we are talking about.
there is probably a way to test the capacitance of the capsule and compare it to the good one. capsules are like capacitors.
Also , check those little plastic pattern and rolloff switches. If it fell to the ground it may have damaged one.
there real easy to break.
After a drop , It is not likely to be a capsule, but I would be surprised if it was. I've seen those mics with drumstick dings
in the grills and they still escape what seems certain death.
if uncertain, as a starting point, try posting a pic of the capsule or mic insides so members here can help you possibly spot a problem.