This is a very common concern for many young players and the solution is very simple. If your instrument was working before you oiled your valves and then after oiling them your instrument will not allow any air to be blown through it, you either have one or more of your valves in the wrong valve casing or your valves are incorrectly positioned in its own valve casing.
Solution to your problem-
Check to see if your valves are in the correct valve casing-
Check on each of your valves for a stamped number. Usually they can be found on the upper section of the shiny part that you push into the valve casing. Each valve’s number will tell you which casing it should be placed in. i.e. first valve in the first casing, second in the second and the third in the third casing. If your valves are in the correct casings, then you need to find out if each of the valves is in the correct position within each valve casing.
Check to see if your valves are in the correct position within each valve casing-
Most modern valves have one or two alignment extensions which are to slide into corresponding slots in each valve casing. Sometimes the valve is inserted into the casing incorrectly and the holes in the tubing will not line up with the holes in each valve which causes the air to be stepped-up as you blow into your instrument. The quickest and easiest way I have found to indicate which of your valves need to be rotated is blow air into your instrument as you one by one depress your valves down. The valve that sounds different from the others will be the one that needs to be rotated. Sometimes you may have two or even all three valves incorrectly positioned and you will have to continue the blowing and turning until your problem has been corrected.
This is one of the most common problems beginning player have so remember this solution so that you can help another trumpet player in your section later this year.
For additional hints of trumpet problems, you might be interested in this post-
