if it works then the sensi is working and the board is detecting that the sensi is working so it is highly probable that your red button is either fooked, or has a small peice of paint shell or dirt in it, switch off the gun and take the board out of the grip then check the button, if it is nacked you could get a new button and solder it (if u are up to skill on soldering) or send it away, or get another board.......but we will cross that bridge when we come to it....it does sound like the button is nacked or dirty tho sensi switches are pretty cheap, they are pretty basic
cheers
Richie
cheers
Richie