I have an issue with what LaPastenague is stating, at least for the sake of expanding this topic and hopefully solve my own issue.
I have an A1409 that had worked flawlessly since purchased sometime in 2011 or 2012. My IT guy set it up and I didn't mess with it.
Sometime around September 2014 I happened to open Airport Utility and noticed an update available (7.6.3). Instead of checking with my IT guy I applied the update. No problem.
Several weeks later I lost internet. Solid amber light and no connectivity.
I poked around and all of the info I got suggested that the power supply was toast or possibly the hard drive. My IT guy came to the same conclusion after doing his own independent reasearch. Notwithstanding, the overall resolve was to replace the Time Capsule. It thought this was BS.
Reason: I had an issued (slow processing) with my laptop after downloading Yosemite and Apple said it was a hard drive failure after running me through various tests. Although I questioned the advice because it started happening immediately after downloading I heeded their advise and replaced the hard drive (Upgraded to SDD and larger RAM) and it fixed the issue. A few days later my daughter and wife updated their laptops (same model and make-up) and they immediately starting having the same problems with their computers (slow processing). I am convinced it is something to do with Yosemite and programing conflicts with HDD drives or some other parameters.
So considering the above mentioned, I decided against purchasing a new Time Capsule and instead unplugged it over night and plugged it back in the next morning. Out of happenstance it worked. Ha I thought. It was a simple fix.
A few weeks later, the same thing happened. Solid amber light and no connectivity. I unplugged the Time Capsule for about 20 minutes (previous trial and error attempts indicated that I had to have it unplugged for at least 20 minutes) and plugged it back in. Sure enough it was back working again. Again, after a few weeks the same thing happened and my resolve was the same.
As time went on I would only get about a week, maybe 4 days, and the Time Capsule would fail.
Convinced it was a programming issue I looked up how to re-install the previous version of the firmware (7.6.1) and found a how-to on how to do it. I went ahead and re-installed the old firmware and it worked. I did not have one hiccup. This was about two months ago.
After I re-installed the old firmware I played around with the setting and now Airport Utility opens up every time I start the computer. Instead of trying to figure out how to shut this off I just close the window. There is that indicator that says I need to update the firmware but I just ignore it.
PROBLEM: About three weeks ago I inadvertently applied the update. I realized my mistake halfway though the process and force-quit AirPort Utility. No problem I thought.
A few days ago we had a power outage and upon restart the Time Capsule had that same amber light. This time my normal protocol for resolve did not work. The amber light would not shut off. Moreover, when I try to do the factory reset (power off; hold in reset button; power up) I am unable.
Theory: My theory is when I inadvertently applied the update and Quit the program some weeks back some of the programing must have been applied. When the power went off and back on the Time Capsule got confused and is hung up.
Any feedback would be greatly appreciated.