In this image, the red 2.5mm DC barrels are not connected to a power source.
You also show a connection here, any splice will degrade the signal and if this is a digital signal such as HD-CVI, HD-TVI or AHD the signal will drop to the point where nothing will be seen.
Please open the recorder and let's try to identify it by MAC address as well as any other stickers on the main board.