DSi doesn't turn on, but charges.

I tried repairing a DSi today, but when I tried turning it on. I thought the battery was dead. I started to charge it, and the charging light was solid, meaning it was charging. I waited 10 minutes and tried to turn the DSi on. I tried this with 3 batteries, and 2 power boards: one that had a fuse bridged, and one that has no bridged fuses. Any help?