Strange problem with composite(CVBS) video system

[Logan]

Hi friends.

I have a strange problem. The devices in question are 6 cameras, 4 power supplies, and 1 monitor.
At first, I found some combination don't work well, then I isolated the issue to a specific PSU.

If that specific PSU is used, the video signal will be at best, distorted and having horizontal moving strips; or at worst, just show "no signal"; or in the middle, showing flashing horizontal bars(no usable picture), indicating bad sync.

The strange part is the PSU is new, and works well anywhere else, ONLY being a bad guy when I connect the monitor and a camera to it at the same time.

I'm thinking, is it possible that some signal make their way into the power line, and that PSU don't filter them well, so somehow gets crosstalk? Or the PSU itself is not giving a clean output? Without a scope I cannot tell...

Thank you.

[CaptDon]

Is this questionable power supply the same make and model as the ones that work properly? Sounds like it has poor regulation or little filtering on the output.

[Logan]

Is this questionable power supply the same make and model as the ones that work properly? Sounds like it has poor regulation or little filtering on the output.

Thanks!
No they are very different, otherwise I'll know it's just a bad one.
I fell it's just bad design problem.

[Terry Bites]

You mean when the FEDs are in your shop?