I had two elite type DVRs all cameras went black. Turns out that the "color settings" went to zero. (hue brightness contrast etc went to zero) Each DVR is about 2-3 years old. One is strictly analog and the other HD-CVI. The analog DVR went black about a week ago. It recorded black for a couple of days. The system was on but no pictures until I discovered the color settings were all reset to zero. This happened once, ok that's a glitch. Oh Hurricane Irma had just gone through Orlando and our electricity was flicking on and off for days rapidly. But then the HD-CVI DVR did the same thing. Two totally different locations, different networks. One is in my home the other a business. 

Is this common? Was my DVRs hacked? Very curious to know.

Thanks

Jerry