Showing results for 
Search instead for 
Did you mean: 

USB and power adaptor (Help!)


Hello, I hope someone may have an answer for me,  I have a rebel T3  and I would like to connect it to my computer and a power adaptor at the same time, to do so I have connected the USB to the computer and have the ACK-10 power adaptor in place of my battery.  When the adaptor is connected my camera works fine and is powered up, however when I plug in the USB to my computer the camera acts like it has a loose connection and powers on and off with the computer connection sound connecting and disconnecting over and over until it just stops and does nothing until I disconnect the usb cable and it works fine again. On the other end of the scale It also works fine on the computer if I have the Battery in use instead of the adaptor.  I have turned off the auto power in the camera menu to try to fix it but to no avail.  Any ideas?  Thanks in advance.



What you are describing are classic symptoms of a ground loop.  The fault lies with either the USB port on the computer, or the power adapter.  Are using all Canon gear for the power adapter?

If you are using a laptop, then unplug its power adapter.

"The right mouse button is your friend."


Does your ACK-10 plug into a USB port? That might not provide enough power to the camera.

Its a wall socket adaptor, I was going to switch to a usb to see if it made any difference.



Then you have a ground loop. Try reversing the plug in the socket.


A ground loop seems unlikely as such a thing as far as I understand pertains mostly to acoustic and sound devices.  But... I reversed the plug, I tried different sockets and grounded space bars.  So i ordered and recieved another power cord with a USB plug instead of a socket, to no avail, same issue...then I thought perhaps the usb to the computer was powering and/or charging the battery so I put the regular battery back in but nope...the battery died.   I am at a loss.


So it looks like the issue was that the Camera was confused by trying to draw power from 2 different sources.  I put a small piece of tape over one of the USB pins connecting it to my computer so it only transmits data and not power.  That did the trick.  🙂

06/10/2022: Service Notice:UPDATE: Canon Inkjet Printer continuous reboot loop or powering down
06/07/2022: New firmware version 1.3.2 is available for PowerShot G7 X Mark III
06/07/2022: New firmware version 1.0.3 is available for EOS M50 Mark II
05/31/2022: Did someone SAY Badges?
05/26/2022: New firmware version is available for EOS-C500 Mark II
05/26/2022: New firmware version is available for EOS-C300 Mark III
05/10/2022: Keep your Canon gear in optimal condition with a Canon Maintenance Service
05/05/2022: We are excited to announce that we have refreshed the ranking scale within the community!
04/26/2022: New firmware version is available for EOS R5 C
03/23/2022: New firmware version is available for EOS-C70
03/22/2022: New firmware version 1.2.0 is available for PowerShot PICK
03/16/2022: New firmware version 1.5.2 is available for EOS-R5
03/16/2022: New firmware version 1.5.2 is available for EOS-R6
02/09/2022: Share Your Photos is back!
02/07/2022: New firmware version 1.1.1 is available for EOS-R3
02/07/2022: New firmware version 1.6.1 is available for EOS-1DX Mark III
01/13/2022: Community Update. We will be retiring the legacy profile avatars on 01/20/2022. Click this link to read more.
01/05/2022: Welcome to CES 2022!
12/7/2021: New firmware version 1.3.0 is available for Mount Adapter EF-EOS R 0.71x
12/7/2021: New firmware version 1.1.1 is available for CR-N 300
12/7/2021: New firmware version 1.1.1 is available for CR-N 500
12/2/2021: New firmware version 1.1.0 is available for RF 70-200 F4 L IS USM