It is fairly unusual for the power supply to blow in the Gen3..
And power supplies for them are pretty rare.. you will find plenty of supplies for gen1 and gen2 on ebay but gen3 is slight higher watts..
You can contact a repairer..
Chris Fackrell in the UK.. (I assume from the fuse in the plug you are in UK).
https://sites.google.com/site/lapastenague/a-deconstruction-of-routers-and-modem s/apple-time-capsule-repairers
Your TC is extremely unlikely to have a bad supply.. Chris and I worked out a repair method.
https://sites.google.com/site/lapastenague/a-deconstruction-of-routers-and-modem s/apple-time-capsule-repair/new-issue-with-a1355-gen-3-tc
What has happened is one of the lousy ceramic capacitors on the board has shorted.. and it cannot start up. It is possible to burn them off.. !! 👿 (devil symbol seems appropriate though I bear no untoward association other than the use of heat to achieve my aims).
I think Chris and I are the only ones who regularly do this repair and so far my experience has been total success.. the failure doesn't return.
You can pull data off the disk if you don't want to go down that path just by pulling out the HDD.
See https://www.ifixit.com/Device/Apple_Time_Capsule
Put it in a USB sata holder.. cradle.. toaster someone called the open disk type.. !!
Airport Extreme - recovering files on removed drive
You can buy a second hand working TC from ebay.. and swap the disk for the 2TB.. even if just briefly..