eagleT12

I have a 2009 G37 that had been having issues with the battery dying after not driving it for 2 days. I replaced the battery last year but the issue didn't go away.
I took it to the dealership several times, the last time I did, I asked them to do a test to try and figure out what it was. They said it was the radio that's drawing current. I took the radio fuse out and it's working fine now. I want to know if after removing the radio, there is a way for someone with little circuit experience to find and fix the issue. I am not able to find any manual online to help with that.