Last week I took my MP 90 S to the range for the first time in a half year only to discover the firing pin don’t appear to be active. When the trigger is pulled it travels but there is no click or sound to indicate the hammer is moving to strike the firing pin. Further exacerbating the problem the trigger guard that houses the entire firing group will not budge for removal. I have the owners manual and have removed the trigger guard assembly for thorough cleaning several times. It is tricky to reinstall but removal is pretty easy.
Update:
I removed the trigger guard. The hammer is visible and is cocked. The trigger travels through its full arc but doesn’t release the hammer. The trigger can be adjusted for pull weight, take up, reset, travel and the angle of trigger face. All of which adds up to some serious reservations about disassembling the fire group.
The firing pin isn’t broken. It is a very thin flat pin. I have read it’s prone to breakage.
Being the pistol functioned fine when last used I’d like to see if I can diagnose/correct the problem before taking it to a gunsmith.
this video show removal of a similar trigger group:
https://www.youtube.com/watch?v=dEZkRq6DqbQ
Update #2
Put my cheaters on and discovered the hammer spur is bent.