Fret Button Malfunction - Blue Button is always on

I recently bought a guitar hero 3 les paul controller for PS3. When I tested it I noticed the Blue Button is pressed automatically every time I play a song. I tried cleaning the contacts on the PCB (Fret Buttons) with IPA and Pencil Eraser. It would work for a couple of songs (meaning the Blue Button is not pressed) BUT it will go back to its previous condition where the Blue Button is pressed automatically. I only played on EASY difficulty, it still gone back to being pressed. Tried changing the (Blue) Button Pads with Gray ones, still same effect. Need help on how to fix this.