Why the picture is so dim?

My camera is Instax Mini 25. I haven't used it for a while. I found that all the pictures I took were all quiet dim when I used it to record a birthday party last week. I also found the flash light of the camera was not bright as it used to be before. So I decided to fix it by my self. Capacitor may be the problem I guess, so I replaced it with a bigger capacitor which spec is 330V, 300uF. Then the flash light didn't work anymore. Even I replace it back to the capacitor the camera used as default, the flash light was still dead. Can anyone help me to fix this problem? I borrowed it from a girl who I was fascinated by. I hoped that I can fix it by myself that would make her happy !