If you struggle do let us know.

Interesting point about the IR because the newly connected camera is an internal IR one, much  closer to the PS than the one that went down

have you fed power by tapping from the new camera to the old one? if so what size power cables have you installed?

to test if the ir's will cause an issue, simply mask both camera (so turning on IR's) and read the voltage at the furthest camera. below 11 vdc then you could also link 2 positive outputs together in the psu, to the supply line which will provde 1amp assuming cables are of decent gauge and not to long.

The fact that the dvr reported loss of cam when you unplugged it suggests it was still giving an output. Maybe the lens got stuck closed?

I've seen video equipment produce sync pulses (which is how "signal") but nothing else when the power is marginal.

I've seen video equipment produce sync pulses (which is how "signal") but nothing else when the power is marginal.

 

Correct. I also say power issue.

 

Try removing the camera you installed.

Try testing the voltage at the camera ends.

Test mA readings from each output.

sounds like the iris was staying closed at the old cam. it happens sometimes, and restarting usually fixes it.

but as others have said, it could be because the power limit was right at the edge. so everything was powering up, but there wasn't enough power to drive the auto iris motor.