Hi Ethan,
I don't have answers for you, but your question was migrated from being an answer on another question to being its own question. As such, something's getting lost in the translation so I was going to try to fill in the blanks.
First off, the original post is here.
[post|830781|It’s not turning on - Nikon Coolpix L20 - iFixit]
As suggested by @oldturkey03, I see you've checked the fuse and according to your test it's good. It appears oldturkey03 was referring to a DC-DC board, not a D20-D20 thing. Again I'm not familiar with your camera, but generally a DC-DC board is one whose job is to convert one DC voltage into a different voltage. For example your batteries might be providing 3 volts to the camera but there could be electronics in there that need, say 1.8 volts and 5 volts. The DC-DC board converts that 3 volt power to the other voltages needed to run the camera. Obviously if that board has died then it won't be supplying power to the rest of the camera that needs it, which is what oldturkey03 was suggesting.
However, I'm going to have to leave it up to him to elaborate on where that board is and/or how to test it.