MR6500 no longer connecting without battery

I purchased a MR6500 from Amazon. I set it up and it worked great with the battery removed and antennae installed. I had to do a factory reset because I couldn't remember my admin details and needed to login into the attwifimanager site. After the reset I tried to setup the Plugged In: Max performance with battery removed.  It says it needs to reboot to enable this mode. I let it reboot and took the battery out, but the device doesn't connect any more. I tried taking battery out before and after the reboot and neither will work anymore. The device just turns black and will not come on unless I reinstall the battery. Is there something I am missing.