The case sensor on the Pro 1000 prevents the primer pin from retracting down far enough so a primer can slide on top (or is supposed to). If you are getting primers when no case is present, the pin must be retracting even though the case sensor hasn't been tripped.
Check to make sure that the straight end of the case sensor spring is in the slot next to the primer pin in the shell plate carrier. Also make sure that the pivot screw for the case sensor is not over tightened, causing the case sensor to bind, and that the case sensor is assembled correctly. The steel bushing should be installed so the small diameter goes through the case sensor.
If primers feed every time, please check the following: The case sensor spring may be installed correctly, but something may still be preventing it from fitting all the way into the slot cut for it in the primer pin pocket. The straight leg of the sensor spring must protrude far enough into the primer pin pocket to fit under the shoulder on the primer pin. This is what holds the primer pin up high enough to prevent a primer from sliding down the trough. Check for powder in the primer pin pocket, or in the slot cut for the sensor spring.
Another possibility is something under the primer trough, preventing it from being pressed all the way down into the shell plate carrier casting. Again, look for powder or other foreign objects.
Last, look for an over tightened case sensor retaining screw, or a sensor bushing installed upside-down. Either will prevent the case sensor from pivoting correctly, and could cause the case sensor to hold the sensor spring in the "out" position.
Please keep in mind that if you have an old Pro1000 (20 years or more) the carriers did not have a case sensor installed on them. To resolve this, you can send in your old carrier and we can replace your old carrier for a new carrier for $10.00.
View Pro 1000 Help Videos: http://leeprecision.com/pro-1000-help-videos.html
