Why does the orange charging light flicker on and off?

My ds lite's orange charging light flickers on and off. The f1 fuse was bad so I replaced it but it didn't do anything. However I didn't know how to solder back then and when I look back at it it's a mess. The fuse does have continuity but there is solder everywhere so it could just be a short. I dont know how to clean solder like this and i could use some tips. I would love answers to this and to possibly other issues that could be the problem. Thank You!