A1254 Time Capsule not powering on

It's amazing that the Time Capsule went as long as it did. A good shop could probably handle the repairs for you if they could locate a power supply.

But, it would make little sense to try to repair a Time Capsule that has a hard drive that is also overdue to fail.

If the data on the Time Capsule drive is valuable to you, have the shop pull the hard drive, place it in a separate enclosure and copy the data over to a new external hard drive.

It has been suggested that failure of those power supplies was due to the ineffective cooling design of the enclosure. The 3.5" hard drive inside it generates a fair amount of heat. Unless someone had a NIB power supply that an AASP previously had in stock (which I doubt at this point), your only option for self-repair or paid repair would lilkely be a used power supply, although a competent repair shop should be able to replace a bad capacitor. Buying and paying for installation of a used power supply that has an unknown number of hours of use could result in reduced service life for you. If you're ready to buy a new WiFi router that supports the latest security protocols and you're ready to e-cycle the TC, you could attempt removal of the internal hard drive as illustrated here. If you damage the rubber base cover, it would be of no consequence at this point. Transfer the 3.5" hard drive to a separate enclosure and continue using it for data backup, without the convenience that the TC provided for the task.

Good plan. Good luck.