eztech

I am exhaustively troubleshooting one of our past installations that is constantly suffering video losses on multiple channels. I would be interested in hearing if any of you folks have any experience or advice regarding these power supplies. The PSU's used are 8 channel 24VAC 7.25 Amp units. These are advertised as 24VAC output but we've had 4 cams DOA at different site visits. At first we were baffled, but upon closer inspection and testing we realized that these PSUs are outputting between 28.5-29 VAC at the PSU. The cams in use are CNB 600TVL box cams, according to CNB tech support there cams have an over voltage protection circuit which attempts to save the camera in the event of over voltage. The tech suggests that the cams should receive no more than 26.5 volts, we have measured 28.3-28.5 VAC consistently at each camera. Is this high voltage output to be expected from other 24V PSU manufacturers?

Ok Adam

ok, so I disassembled the box cam that recently failed and was surprised to find this. The yellow wire was pinched between the power board and the housing Notice the melted bulge in the power supply Here is a pic of the housing where the conductor eventually meted through its sheathing Here is another pic of the housing to see the manufacturer name l

They were cabled with coaxial originally, we took a shot in the dark and re cabled to cat5e with baluns about 2 months ago. the Baluns use one pair connected to terminals on the baluns. The system generally has no video distortion and no ground loops. It varies, the 2 with no video in the pic are probably permanently damaged. Some will go on and off for a day and then be fine. Sometimes a month goes by without any issues.

Then I am at a loss. We install these CNB cams ( CNB-BBM-24F and CNB-V2815NVR) all the time. We use these power supplies all the time. Anyone have a clue what might be happening here? This always happens surrounding inclement weather, yet none of the equipment is getting wet, no lens fogging, nothing. If anyone here has any solutions or avenues to search please let me know at your discretion, Thanks Here is an image of the issues I'm having Here is the Layout of the Installation www.indecomaz.com/Files/CCTVPlan2.pdf

The AC input voltage is high, we've been monitoring that for about 2 months and the voltage ranges between 117 - 123 volts.