/vr/ - Retro Games

I've always had this random power adapter that I always used with my Famicom with no problems. I did some rearranging today, and when I turned on my Famicom nothing happened. After trying a bunch of things, I decided to check the voltage on the power cord, and all of the sudden it was at like 15.5 volts dc. It had worked flawlessly for more than a year so this was really strange and unexpected. Admittedly, I had never actually checked the voltage before but it had worked fine so I never bothered checking. How can I prevent this from happening in the future, and is my Famicom completely fucked, or is there like a fuse or something that just needs to be replaced? Thanks /vr/.