I have a Porter Cable Quick Sand Model 333 5 Type 4. While using it I heard a noise and thought I saw something fly out the dust container tube. I didn't have the dust container on. Then the sander no longer was a orbiting sander. I just spins in a continual pattern.

SOURCE: Sander does not turn on when power is applied

could be a couple things but I am going to guess the switch is contaminated and keeps tool from running. The switch number is A22667 and lists for 2.81. What you can do to find out possibly is hold tool up and in rapid sequence turn tool on and off and sometimes it will move enough dirt to operate. Let me know if you need any more assistance

SOURCE: My porter cable orbital sander, model 333 needs to be lubricated

how to lube sander

SOURCE: Porter Cable Random Orbital Sander rotates but does not "orbit"

Just solved my problem with Porter Cable 333 orbital sander which just groaned. I thought the worst. I carefully took it apart on the garage floor and immediately suspected it needed lubrication as the motor turned hard. I used my flexible long plastic tube lubrication and put some on the bottom bearing shaft the best I could. I worked it around and around. I began to feel it turning easier. I applied more oil and kept moving and it became completely free. I put a drop on the top bearing even though it was loose. I put it all back together and it works like new. Lesson: do not look for the worst when a tool quits. Suspect the culprit to be lack of lubrication!!!