Mamba interference shielding sheets, are they harmless?

Hello guys,

I have been using this [Mamba interference shielding](https://www.diatone.us/products/mamba-in...elding-fpc) without apparent issues until yesterday and today I found something strange:

I connected the ground pad of this sheet into the ground pad of HGLRC Zeus F722 Mini just right next to the 9V BEC pad normally for DJI Air Unit power supply. But I’m not using the 9V BEC, I’m only using the 5V pin to the Zeus VTX Nano. I connected the ground of the VTX to the ground pin next to 5V

This is the exact same wiring according to schematics shown on HGLRC website. Everything seemed fine until I put the Mamba interference isolation sheet on top of the ESC. I ran the motor wires on top of the ESC. So, those motor wires will touch this Mamba sheet when installed.

I plugged the battery on, and there’s only black screen on my analog goggles receiver. No OSD, just black. Then I move the sheet away from the ESC into the empty air just hanging with the ground cable connected. Then video becomes normal and clear.

So, I decided to remove the isolation sheet. Then I noticed something really weird. Normally if I measure capacitance across battery lead I would get at least the value of capacitor + some extra capacitance in the ESC / FC. In this case it should be 1500 uF. But, I only read 500 uF when the mamba sheet was installed on top of my ESC. I removed this sheet, capacitance readings are normal! What’s going on?

I don’t understand electronics deep enough to understand what’s wrong with this Mamba sheet coupled with the wirings of my motors + the electromagnetic effects of the ESC.

On some ESC’s like the Holybro Tekko 32 4in1 a thing copper shielding tap is used to reduce noise.

Although some recommend the shield to be connected to a ground pad, I have never done this.

I would suggest you de-solder the ground connection between the interference shielding.

(04-Apr-2021, 11:06 AM)kafie1980 Wrote: On some ESC’s like the Holybro Tekko 32 4in1 a thing copper shielding tap is used to reduce noise.

Although some recommend the shield to be connected to a ground pad, I have never done this.

I would suggest you de-solder the ground connection between the interference shielding.

QQ, given its coper I'm assuming you need to make sure it does not come into contact with any metal, FC, screws ect ?

(22-Jul-2021, 01:50 AM)fullofhotair Wrote: QQ, given its coper I'm assuming you need to make sure it does not come into contact with any metal, FC, screws ect ?

Yes, please avoid contact to avoid shorts.