RBS750 satellite won't stay connected to RBR760 router

Hello, can someone offer some new suggestions as to how I can get my RBS750 satellite to hold its connection to my RBR760 router?  I updated my router to the new RBR760 (came with other 2 satellites from Costco) because my previous router RBR750 stopped working about two weeks ago.  This satellite was working when I had it connected to my previous router.  But it's not working with my new RBR760 router.  It would connect for a minute or less then drop its connection.  These are what I have done so far:  I have factory reset it, updated to the latest firmware (RBS750-V4.6.9.11), connected directly to the router via ethernet and while connected to the router it would drop its connection...so I don't think proximity to the router is the problem. I've also connected using the same ethernet that I use to connect to the two RBS760 working satellites, and it still doesn't connect to the router.  Both RBS760 are upstairs and connected via ethernet.  Is there anything else I can do or is the problem with the satellite just not working anymore??  Thank you in advance!!