I need "A" quick fix

[Scotti Adams]

Okay..I got a mando here that is noting off just a tad on the second A string...not alot but enough to screw with me. Its noting sharp with the first A string...I dont have time to get it in to get it fixed before my next gig..so..what are my options?..yea..the frets need a good dressing. Ive always have been able to fix these things but this on has eluded me...can you guys help..??

[sunburst]

Just one A string?
That's probably in the nut. Take the A strings out of the nut and look at the slots with a magnifying glass. You should be able to see where the strings rest in the slots. If both imprints don't go all the way to the front edge of the nut, they need to be filed so that they do.

If the nut slots both look good, then it's probably the bridge. Do the same thing as the nut.

If all four string slots look good, then it's probably the strings. Change the strings and see.

Luck.