Weird intonation problem !!!

[John Rice]

Hi, I just got an Epi Dot into the shop which has a strange intonation problem which someone may be able to help me with. The only string with the problem is the low E, when it is tuned to pitch E it also reads E at the 12th but when pressed at the first fret it reads F# I have adjusted the bridge to both extremes and all stops in between, retuned open and 12th but still it reads F# at the 1st. I have checked the scale length, fret positions, nut and bridge height anything I can think of but no success. F# at the 2nd fret is also sharper and on down the board until D and D# when it eases back to E at the 12th. Any help would be gratefully received Thanks.

[Bob Gramann]

If the working edge of the nut has crumbled back toward the tuner, it will cause significant intonation problems, but usually not that bad. Make sure that you have a good string--one with uneven mass along it's length will not intonate well. And make sure that your electronic tuner isn't lying.

[Barry Daniels]

Could be a bad string. How are you gauging the intonation? By ear or do you have a tuner?

[John Rice]

Thanks guys,the first thing I did was replace the string so that should be OK, I am in fact using two tuners as I didn't believe the first one but it showed the same reading,it's a really strange one. by the way Bob I made a beautiful guitar from that Cypress set I got from you a few years back must post some photos of it.

[Bob Gramann]

Glad to hear about the guitar. I thought I recognized your name. Did you mean Sycamore?

Make sure that the last place the nut hits the string is the edge toward the fingerboard. If the nut slot has crumbled or has the wrong slope on it, it will wreck your intonation.

[Michael Lewis]

Have you measured distances from the nut to each fret and compared the measurements to a calculated fret scale?

As asked previously; how is the string slot in the nut? Where does the string make contact?

I know you changed the string, but bad strings can happen, so try another.

The physics involved seem to lead to the string contact point in the nut being too far from the first fret. It can help to use a magnifier to visually check the string/nut contact process.

Are the first couple frets high? Especially the 2nd.

[Joshua Levin-Epstein]

Does the string sound (as opposed to reading) like F# at the first fret?

[Mark Swanson]

Try placing a capo on the first fret, and then re-tune the guitar. Is the problem still there? Like the others mention I think it is a nut problem and eliminating the nut and then checking the tuning may help confirm it.

[Joshua Levin-Epstein]

You might also try lowering the bass side of the pick ups. This problem is more common with Fender style pick ups, but I have seen it with humbuckers, as well.

[John Rice]

Thanks again guys that gives me lots to be going on with. Sorry Bob I did mean Sycamore

[John Rice]

Hi guys I'm back I think I have it solved. I tried all you're suggestions for which I am very grateful but nothing worked so just on a hunch I put a D string on it not for any special reason but just because I had one to hand tuned it to E and bingo just like magic it intonated all the way down the board. So I think with a lighter set of strings maybe 9s it should be OK even though I still think it's weird.

[Bob Gramann]

Maybe the nut slot is too narrow for your normal E string to drop down into it?

[Mark Swanson]

If your guitar will not work with 10's or even 11's then something is still wrong. And really, one of our suggestions should have nailed it.

[Stephen Neal Saqui]

You haven't solved anything!
Does it play in tune to your ear? (This was asked before)
Did you change the string with a new one?
Did you make any change with the nut? Does the nut fit the slot? Is there a gap under the nut on the bass side?
The fact that a D string works, doesn't mean you must use lighter strings...but it may mean something else.
Don't quit, thinking you've "solved it"!!!

[Matt Cushman]

Is the low E saddle maxed out to the back of the bridge? Some of these Epiphones max out short of correct intonation on the low E string. I have seen at least 2 that had this problem.