My recommendation is to seek out methods to contact Arris about the problem. It sounds like a defective unit.  I searched for and found a link to text chat with a company rep (even though I think he was in India) but he helped me enormously with my problem and was integral in helping me alleviate the problem.  Sorry, I don’t have the link and would have to retrace my steps taken months back to find it...again sorry, don’t have the time to do that.

Hi Rentzboy 

To check on SBG8300 please contact arris.com/consumersupport for further assistance.

Thank you.

To those who may have the same issue.. since my router was purchased on EBay there was no warranty or support so with nothing to loose except my purchase price … I took the modem apart. There is one screw on the bottom under the warranty notice. Then you have to remove the bottom it slides into slots… just push right or left depending on orientation…then remove all three adhesive stickers one on back one on front one on top then remove 2 screws under adhesive sticker on top….then pry apart… I removed the heat sinc… scraped off dried thermal paste and reapplied … worked like a charm. So over heating was the issue even though it wasn’t “hot” to the touch. It’s been powered on for 3 weeks uninterrupted.

Another point the method used to determine it was over heating was powered it on and sit it in my freezer for several hours … it never powered off… it had progressed to oowering off every 5- 6 minutes before I did the freezer test.

In this case we would suggest you to disconnect the modem from power and please contact Arris customer support for further assistance if the modem is under warranty please do access arris.com/consumersupport