bassman.dxb

Hi chaps. I'm struggling with dead spots only on my A string, action is raised but the A string is noticeably quieter than the others. E / D / G strings all perfect! This is my 3rd Washburn and 2 of them had the same issue, last one was never solved, sold it on cheap to a guy who wanted to try and fix it. Any suggestions? Love the bass but this issue is making it unusable in a gig environment.