Help! 2 cameras fried by monitor - anyone had a similar issue

[Andy Mcleod]

Hi Folks,
We took delivery of an external underwater monitor which we bought from a manufacturer who built the waterproof casing, and they used a Feelworld HD-SDI monitor sealed inside. It came with a 4 pin waterproof cable which plugs into the monitor and the camera housing. Inside the camera housing the cable splits into a BNC plug for video and a D-Tap plug for power. On testing the monitor powered showing the Feelworld logo, but no HD-SDI signal from the monitor. We tested it with 2 cameras, a Dragon and a Gemini without luck. When we attached another monitor, there was no picture either, and it turns out the Feelworld monitor has fried the camera board with the HD-SDI output. We have since been advised by the RED Service Centre that monitors should be plugged into the power first, then connect video. In 25 years, I have never hear such a thing!
Does anyone one have any thoughts or experiences with such issues. We have a hefty repair bill which hurts!
Best Regards, all.
Andy

[Johnny Hurberg]

First of all, so sorry to hear about the repair costs!

Read about for the first time myself a couple of month ago

https://www.newsshooter.com/2020/02/...o-sdi-outputs/

[Jacek Zakowicz]

I rememmber long time ago we ended up using video ground loop separators because of that. Audio guys have done that for ever. Putting common ground on power and video is not the most fortunate idea....

[Andy Mcleod]

Thanks Johnny. Super helpful article... I had no idea!! Cheers, Andy

[Nikhil Kamkolkar]

I rememmber long time ago we ended up using video ground loop separators because of that. Audio guys have done that for ever. Putting common ground on power and video is not the most fortunate idea....

Jacez, can you please elaborate on what video ground loop separators are? Would using this remove the need to follow the procedure above where you connect all power to all accessories first and then connect the BNC cables?

I'm also reading that this only occurs at the point of connection or disconnection of the cable, but changing batteries etc., should be no impact.

This is quite an important bit of news that I think should be broadly propagated to everyone working with all cameras with HD-SDI outputs.

Thanks,
Nikhil

[Jacek Zakowicz]

Jacez, can you please elaborate on what video ground loop separators are? Would using this remove the need to follow the procedure above where you connect all power to all accessories first and then connect the BNC cables?

I'm also reading that this only occurs at the point of connection or disconnection of the cable, but changing batteries etc., should be no impact.

This is quite an important bit of news that I think should be broadly propagated to everyone working with all cameras with HD-SDI outputs.

Thanks,
Nikhil

Ground loop separators are mainly used in audio to minimize the noise. These are little boxes with two sets of coils that completely isolate the grounds and operate on induction principal. I'm not an electronic engineer so that is all I can tell you but we used them in our recording monitors that were used on cranes to separate the ground that otherwise routinely fried the video boards with the spikes from the crane massive power draw.... the article linked above seems to suggest similar issue...