iMac FaceTime HD camera shows no image/black image There's an iMac whose FaceTime HD camera isn't displaying video images in applications like FaceTime, Photo Booth, or QuickTime video recorder.

OS X El Cap shows that the camera is attached and registered properly in the About This Mac - System Report.


fresh new install of El Cap on a Fusion drive. Previously the camera worked well with Yosemite. 
the green light indicator flashes on/off repeatedly and irregularly when you start an application that uses the camera
there are no error messages or anything about no cameras being attached.
pressing the big button to take a photo in Photo Booth has no effect. The button is on the screen, but isn't pressable.
Skype is not installed


What steps can I take to get the camera to capture and display video properly?



Attempts to fix


reset the NVRAM


Items to investigate


should I reset the SMC?
will the Apple Hardware Test reveal anything


I recently opened this iMac to install an SSD. All cables were re-attached properly.
I have had this problem in the past. I found my answer here. http://osxdaily.com/2013/12/27/fix-there-is-no-connected-camera-error-mac/
Open terminal from the utilities folder in the applications folder. Type sudo killall VDCAssistant into terminal and click enter.
Then, enter sudo killall AppleCameraAssistant (may say &quot;No matching processes were found&quot;, this should be fine). That should do the trick.