alexsiliato wrote:Here are photos of me testing the SDI port with a multimeter and getting a reading of about 5v from the sdi port itself.
FWIW
I would expect that when metering across the SDI with a DC VOM that you should get 0 volts DC.
AFAIK the SDI (serial digital interface) is an 800 millivolt peak-to-peak HF digital signal.
So you would require a scope to see it as most consumer VOM's won't measure up to its frequency.
At most you may see a very few mV depending on your VOM.
The SDI Out BNC connector shell/shield appears to be connected to the camera's common ground, which includes the camera case, DC Power Input ground, Thunderbolt port shield, USB port shield, etc.
The TRS Audio Inputs do appear to have isolated sleeves however. Probably to prevent audio ground loops.
I would suspect that if your SDI is reading 5V across the BNC connector when the camera is connected to your external battery plate, and nothing is connected to the SDI, that there is something odd going on.
When I connect either the BM AC charger or an external DC battery pack to the camera, I do not read 5V DC on the SDI connector.
When the camera is connected to an external battery source, if you were to read a voltage differential between the SDI connector's shell/shield and the battery pack's ground, then I would suspect a broken ground connection on the SDI BNC, and possible issues.
However, that is only speculation as I have neither disassembled my BMCC or seen the schematics.
David R. Green - Demenzun Media Inc. - Author Composer Filmmaker Programmer