roland vdrums head

I'm having a problem that I hope which there is a simple solution. First, a bit of background; I bought a used set of td 12 drums which have all nylon heads a couple of years ago. I've never changed or tightened the heads until just the other day in which I tightened the 12 inch snare, or I should say I reapplied the head that is to say i unloosened the head and retuned (?). Anyway, since then I'm getting no sound other then right in the middle of the head. No sound when striking on the rest of the head. I am getting sound on the rims (hoops). This is really a drag for I was psyched for practicing again. I hope you guys can help me in this matter. I should say I tightened the head while putting pressure on the middle of the head (usual way for acoustic drums) and maybe I shouldn't have done that because it probably put pressure to the sensor. One other thing I can't seem to get a good open and close sound (ssshup) when striking and instantaneously opening the hi-hat like acoustic hi-hats. Is this par for the course with electronic hi-hats? Thanks in advance.

You probably pushed the sensor cone down and now it doesn't make contact with the head.
It should be 1/16 to 1/8 inch above the shell edge.

If that doesn't fix it, you probably broke the sensor. Don't worry. They're cheap to replace.

I'm unfamiliar with the TD12 settings so can't comment on the hihat.