H-H, could you provide a useful hint perhaps?
Its all about the overall multi-cam system design and multi-cam rig construction.
i.e. NO RATS NESTS when wiring the multi-cam rig.
As per pervious multi-cam posts the multi-cam rig doesn't scale up without additional
trivial issues becoming NEW and significant problem's.
So to eliminate problems, due to the multi-cam power supply related issues :-
## Gradually Substitute camera battery's in-place of the common power supply.
## Use well proven "Industrial Wide" techniques, such as in post #17,
i.e. "Distributed" power supply filtering in the dummy power DC-Coupler's.
## Try to avoid ground loops by rewiring or adding ferrite cores.
## Try to avoid accidental ground loops via USB cable and 1/4 inch camera mount's.
i.e use photo-couples for camera sync as per pervious posts.
## Use a slightly higher supply voltage and Voltage regulators, such as in post #17,
## Try to avoid potential "Common Mode" power supply problems.
If all the above stuff fails you the need to attempt to measure the problem some other low cost way.
## Use a low band radio receiver to detect any RF-Noise.
## Use a simple, low cost transient dector, details later if required.
## Use a passive simple, low cost current to Audio, converter.
H-H