Leaderboard

I would suggest checking your power side connections too. I had one camera break a negative wire, and it still worked but caused an interference on its channel and the matching one (Hikvision DVR). As soon as I reconnected the wire both cameras were fine.

Ghost. Try a new brand cable.

When you changed the power adapter it may have allowed the camera to default to a different setting as tomcctv said check if the camera and DVR are set to PAL/NTSC (they should both be set the same)

Hi I would keep testing simple ...remove camera and plug it into another location ..... if this is just a camera swap to start with it could just be the camera faulty are you using standard analog analog or HD ...... and have you got the right region camera PAL / NTCS

Sorry just read your post again and seen Coax in the title. Check the termination switch/setting on the DVR if there is one! Using a voltmeter set to Ohms go to the camera and check the resistance of the coax cable as it goes back to the DVR, it should read 75 ohms plus the resistance of the cable so probably about 80 - 100 ohms depending on the cable length/quality. If you are reading in the M ohms range then the cable is un-terminated, or has possibly been damaged, next go to the DVR and remove the camera signal lead and measure the resistance of the video input this should be 75 ohms.