Since its over 2 years old, the device repair would be out of pocket. According to Garmin's repair page that model ( 320 ) has a flat rate repair cost of 170$
If and when you want to proceed with an authorized repair, you can use this link http://www8.garmin.com/support/outofwarranty.html
Id like to try some repairs with you and attempt to avoid that expensive repair cost or replacement cost http://amzn.to/1NZryzD
Lets try a master reset first..
To perform the master reset:
- Turn off the Astro
- Press Map, Enter and Power simultaneously
- Wait for Astro to power on
- Release Power
- Wait for the message Do you really want to erase all user data?
- Release remaining buttons
- Select Yes
Astro 220 or 320 is now reset. Leave the device outside with a clear view of the sky for a minimum of 20 minutes to acquire satellite data.
Once that's complete.. Start the device and let me know if it can see any map?
If it can, but you cant see the southeast TOPO map or a secondary map you added. Let me know if you have more then one map loaded onto your SD card.
On a side note, its not mandatory that you and I try and fix the device before you send it off for a repair. But I'm willing to try repairing it with you, if you're willing to work with me.
Should you encounter any issues with the steps above, please send a detailed reply so I can assist you further as needed.
Senior Technician and Network Switching Systems Operator / Maintainer.