if you have sound... you dont need to bridge the sound fuse. if you have sound test the psp without the faceplate. the pressure may be causing a short somewhere. if thats not the problem do was fOOKZ says. see if your LED's are in backwards lol.
what LEDS are sound readtive on your psp? if they are the ones in the video... like the buttons and the umd door... you may have a short. if your LEDs are touching a power source(a short), the leds will be a solid color and not blinking to the sound.