To be able to access the data on the Time Capsule's internal hard drive will require that you remove the drive from the base station. Then place the drive in a drive caddy or enclosure. Finally, connect the drive to the USB port on a Mac or PC. For there, you should be able to access the drive. AirPort Time Capsule Model A1409 Disco Duro Replacement
See if any of the following articles can help: (1) Airport is warning of overheating - ASC (2) why is my airport extreme overheating - ASC (3) AirPort Time Capsule A1470 (Mini!) Teardown - iFixit (4) Repair AC version Time Capsule or Extreme - LaPastenague
No, you cannot use an SSD to replace the AirPort Extreme card in your 2014 Mac mini. Although, OWC offers "data doubler" kits to add a second HDD or SSD to a Mac mini, they do not currently offer a kit for the 2014 model.
The Apple AirPort base stations CANNOT extend the wireless range of non-Apple wireless routers. That is because they use a propriety method to do so with other AirPort base stations. However, the AirPort Extreme base station can "extend" other non-Apple wireless routers if the connection between them is wired. On the other hand, the AirPort Express base station can "join" an existing non-Apple Wi-Fi network as a wireless bridge to share a USB printer.
After verifying that the AirPort Extreme card is firmly seated AND its wireless antenna connected is attached, give the following steps, in order, a try. Stop if a steps resolves the problem. Step 1 • Open a Terminal session. The Terminal application is located in /Applications/Utilities. • At the command prompt, enter: ifconfig -a • Locate the network interface that is giving you trouble. (Note: en1 = AirPort) • Look to see if Terminal indicates the problematic interface is not enabled. (Note: Enabled = flags: UP, status: active) • If not enabled, enter: sudo ifconfig en1 inet up • At the command prompt, enter: ifconfig -a • Verify that the problematic interface is now active and various network interface related data should now be listed. Step 2 • In Finder, go to /Macintosh HD/Library/Preferences/SystemConfiguration • Move (not copy) the preferences.plist file to the OS X desktop. • Restart the computer. • Verify if you have connectivity. If not, go to the next step. Step 3 • In Finder, go to /Macintosh ...
Based on your comments on the status LED, most likely, the power supply in the base station has failed. Ref: AirPort base stations: About AirPort base station status lights (LED) One possible means to try to revive it would be to perform a "factory default" reset on the base station. You may need to try this a few times. If this fails to solve the issue, you will need to replace your base station.
A solid green status LED is normal. Unless you used the AirPort Utility to change this LED to blink on activity, it should remain solid and not blinking. Ref: AirPort base stations: About AirPort base station status lights (LED)
A persistent, flashing amber light indicates that any of the several potential conditions may require your attention: • The base station has not yet been configured because it is new, or the reset switch has been set. • You have selected a security configuration that is not recommended. • A new firmware update is available for the base station. • One of several other conditions, such as a disconnected Ethernet cable or invalid IP address has been detected. ref: AirPort base stations: About AirPort base station status lights (LED) To find out why your base station's status LED is flashing amber: • Open AirPort Utility • Click on the AirPort base station • Look for a Status setting in the small window that appears. Note: Status only appears if there is an issue or notification. Click on the small amber dot there and another window will open to explain what the "issue" might be.