Aquaclear 50 problems?

[fishman3]

I was replacing one of the sponges in it and when I went to plug it back in nothing happen. OK i thought It was just the outlet I was using,So I unplugged my air pump and plugged it into the same outlet and it worked.So is my AC50 clogged or did the motor burn up?

 

[FishEggs]

There might be something stopping the impeller not letting it start. Do you know how to take the motor off and pull out the impeller?
I sometimes get tiny snails in there and once the impeller stops they move and the impeller cant start again because they are in the way.