I have a late 80' Peavey foundation. I tune to standard EADG. The open A string sounds dead, there is lower output from the pickup, and a clanking noise. Fretted notes ring loud and clear on the A sting, every other string rings loud and clear for open and fretted notes. I'm thinking I need to check the nut, and the A string tuner. The clanking noise has me worried, it sounds like it could be the truss rod, but I'm surprised I only hear it on the open A. Any ideas of other things to check? Anyone have a similar experience?