After power failure, 2 MongoDB Servers just won't start again.

With one I get: :

WiredTiger error (0) [1491533102:978650][31243:0x70b9da9a2dc0], file:WiredTiger.wt, WT_CURSOR.next: read checksum error for 28672B block at offset 9068544: block header checksum of 0 doesn't match expected checksum of 4059665721

And the with other :

WiredTiger error (-31802) [1491534981:938109][32667:0x65917b0f2dc0], file:collection-30-4121866540730348039.wt, WT_SESSION.open_cursor: /data2/instagram_bak/collection-30-4121866540730348039.wt: handle-read: pread: failed to read 4094 bytes at offset 2: WT_ERROR: non-specific WiredTiger error

Would you be willing to try repairing our .wt files for both our servers separated by 2 set of files that i've attached ?

And also would you be able to explain the methods used to perform the repair attempt ?

Thanks