[David I Am]

At the risk of being obvious… disassemble and find the part that isn’t seated/is leaking. You’re probably dealing with an old cracked seal – either on the wind chest or one or more of the valves.

If no matter how hard you blow you don’t hear a whisper of a note, its probably the seal around the chest. I haven’t had that particular model in pieces yet, but my experience with other models indicates its likely a two-part plastic chest with a rubber gasket around the outside edge. Replacing this gasket would be my first attempt. Making sure that the plastic internals aren’t actually cracked while I’m in there. If they’re cracked, you could use some silicon caulk to seal it I suspect.

If it still leaked, I’d have to see about the key valve seals.