Dead Yún: Can these be repaired?

I have 4 Yún's. One of them has gone belly up... No response at all... "ON" led lit, "USB" led - half bright... No reset, Restore works at all. Did some comparative probing and found a test point in the voltage reg area with ~2.5V on it on a good board, but 0 Vdc on the bad board. Schematic says 2.5 V comes from the LDO ("Low Drop Out"? ) voltage regulators under the metal shield???...

So.. I give up.... Can these things be repaired? I hate discarding 80 bucks. Who? How?

I really don't want to buy another board and have an integrity lapse and return the defective on in its place.... I could not live with myself... I want to follow an honest process to get this thing repaired. (Picked it up at a local Mini Maker Fair Maker Shed.) a few months ago.

Thanks

2.5V is coming from internal low-dropout (LDO) regulators inside AR9331. if 3.3 V as well as 5 V at shield is fine, then AR9331 could be bad.