I have an old 1976 ibanez LP custom clone that I put some new tuners on, after the change I strung it up with some 10 gauge boomers. But it had some very weird intonation issues that I cant explain.
It played perfectly in tune everywhere except the 3rd, 4th, and 14th frets on the A and D strings where it would be extremely flat. Like if you fretted the A string at the 2rd fret it was perfect, but move up to the 3rd/4th frets and it was dead flat, back to the 5th and it was perfect again.
After changing the strings to a new set of the exact same kind of strings it seems to have fixed the problem. Is there any other reason that this problem would occur and is there anything else I should double check on the guitar?