Might have solved persistent “Err” on D810 and D850

[Dave_In_Oz]

Hi

When using BYN to drive either a D810 and D850 I was regularly getting the camera disconnecting and the LCD on the camera showing “Err” and being very difficult to clear the error. I even had a Nikon service tech look at logs and nothing obvious was there. 
 

I  solved clearing the Err msg by disconnecting the USB cable  to the PC and pressing the shutter button. Whilst the cable was connected, turning the camera off and back on did not clear the error, nor did attempting a reset (two green buttons). It was not until the USB cable was pulled that it would clear. 
 

Physically on the camera I noticed when this error occurred the mirror was partially retracted and did not return to its normal dormant position. 
 

In my case the actual root cause of the Err message was a most likely the use of a USB powered battery dummy as an alternative to a a real battery in the camera. I have a number of these and all had been tried, so I thought it was the camera. 
 

The dummy battery was a typical USB-A. I’ve not tried a USB-C dummy. 
 

I hope this saves some from spending hours and $s chasing the same problem

[astroman133]

What is your USB-powered battery dummy connected to? Is it a powered hub? How long is the cable?

[Dave_In_Oz]

Hi Astroman

Sorry about the slow reply, I have been out of action.

I was using the standard Nikon supplied USB Cables off a powered hub to the actual camera and the USB dummy was connected to a powered USB Hub. I also used a direct to PC (Intel NUC) connection for both the battery dummy and camera control USB cable.

Going further up the power supplty line I was using either a 12V battery pack with 2.1mm jacks, or the mains power packs to power the USB Hub, computer and mount etc. 

The key difference was the camera did not "Err" when using a real battery but always did with the USB dummy battery. And I tried multiple USB battery dummies.  I suspect they probably all originated in China and probably from the same manufacturer despite being different brands .

Also this only happened when I was using BYN to trigger the shutter whilst on the USB Dummy. My theory is the action of triggering the shutter via USB control (BYN) caused a peak currentdemand on the dummy that was higher than the dummy could supply.

Last week I purchased a Pegasus PowerBox Micro which has 12v in and multiple 12v out ports.  I also purchased their battery dummy for the Nikon EL-EN15.  The dummy plugs into one of the PowerBox's 12v sockets.

https://pegasusastro.com/products/pocket-powerbox-micro/

https://pegasusastro.com//products/battery-couplers/

I repeated my testing on both the D810 and D850 and had no failures.

The software for the PowerBox has a panel that details power consumption, if I get time I will try to work out the draw a shutter activation triggers, remembering it has a 12V source rather than the USB;s 5v source.

[admin]

This a great news, happy to see things are working again.

[astroman133]

Great new. Thanks for letting us know that you are working.