I decided to post this because I saw a different thread discussing how long it took several members to fix valves (primarily un-numbered valves) when they were mixed up.
I've had this happen, and found a good systematic way to approach the problem with any valved instrument....It' important to follow the directions carefully in step by step progression.
1. Start at the valve that the lead pipe feeds into. This is the third valve on most modern trumpets/cornets, but it can be the first valve on varying models.
2. Test each valve in that valve casing by installing the valve, then blowing air through the lead-pipe. When air moves freely with the valve in both up and down positions, you've found the correct valve for that particular casing (As mentioned elsewhere on the forum, some valve types can click into position two ways....one is correct, the other is 180 degrees off from correct. If you have an instrument type that will do this, be sure to try the valve 180 degrees different to be certain it doesn't work in that direction.) test valves accordingly until you find the correct valve for this specific casing.
3. Move to the next closest valve casing and repeat step 2 until you have all three done. Should take less than 10 minutes. Essentially a process of elimination starting at the beginning where the lead-pipe feeds into the valve block.
Hope this helps someone save time in the future :)
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