It seems that you are having some issues with your Slingbox PRO-HD power supply since it does not work in a proper way.
This behavior might be related to a faulty power adapter. I recommend you to check the following link in order to apply some troubleshooting steps:
If the issue persists, I encourage you to give us a call. The following article will provide you with the contact information. Just make sure to use the information located on the right hand side of the screen:
Hope this helps!