take the connector from the top of the tilt and the side of the tilt and jumper them to see if the game sees the tilt?
That will tell you if it is mechanical/ in the tilt bob itself. If it works when connected direct then you know you need to clean things better or check your connection.
All a tilt bob is, is a normal open switch. When the bob hits the ring it closes and gives you a warning (or tilt depending on game/ game status)
Figure that out ans then work on the next step