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Intonation Kikin My Ass


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I had a few guitars in from a guy for neck work, hardware overhaul, upgrade bla bla bla. Everything went fine apart from one guitar. An Ibanez Jem7VWH, Son of a bitch just wont intonate properly.

The G & B just dont sound right & I cant get them to intonate the way I want no matter what I do.

The guys Tech was hving the same issue with it but just refuses to send it back to the factory as they have had it so long & hate to be beaten by a problem gitir.

Anyway. Its a late 90's JEM7VWH with a gold edge trem. Anybody any previous issues with intonating these ?

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My suggestion is to make a chart with measurements of each note of each string with a good tuner that can indicate deviation in cents. One guitar I had in had the same problem and after doing this I could show the customer that this was the odd "one in a thousand" guitar that actually has the frets placed incorrectly. This particular guitar had up to 18 cents error in some frets. No wonder that guitar was impossible to get to play nicely...

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2 things I have experienced that cause problems like this are: an improperly positioned, or slotted nut, and believe it or not...the fretwire. When doing a customer setup I ALWAYS have the customer there to play the guitar as I'm intonating it. Jumbo fretwire can be a pain when a customer/player has a heavy "touch". I actually changed my playing style to a lighter touch after I started working on guitars to better compensate for the problems associated with G & B string intonation.

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Bstrd of a thing is driving me nuts.

After I refretted it & it wouldnt work, I went back & ground the frets realy low. I mean micro fret low. No difference !!

The neck is bolt straight & matches its 2 siblings in a crap load of dimensions so Its not big frets, not sqewed nuts, not neck movement. Not any sort of misalignment i can find

The pickups are backed well off of the strings as the player has them almost level with the pickguard anyway. So its not that pulling thing you can sometimes get on oddball gitirs.

So then I replaced the bridge, posts & nut (I like the guy, so pull all the stops here) & TA DAAAAA !! it fookin worked perfectly !!

Untill this morning when I checked it again. back to the same problem as when I got it.

The player thinks its funny because his usual tech has been fighting this thing over a decade & he cant get it either. It plays better now, but still wont intonate properly. ***.

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Bstrd of a thing is driving me nuts.

After I refretted it & it wouldnt work, I went back & ground the frets realy low. I mean micro fret low. No difference !!

The neck is bolt straight & matches its 2 siblings in a crap load of dimensions so Its not big frets, not sqewed nuts, not neck movement. Not any sort of misaligment I can find

The pickups are backed well off of the strings as the player has them almost level with the pickguard anyway. So its not that pulling thing you can sometimes get on oddball gitirs.

So then I replaced the bridge, posts & nut (I like the guy, so pull all the stops here) & TA DAAAAA !! it fookin worked perfectly !!

Untill this morning when I checked it again. back to the same problem as when I got it.

The player thinks its funny because his usual tech has been fighting this thing over a decade & he cant get it either. It plays better now, but still wont intonate properly. ***.

& as if to rub salt in. the chick is messin with it here, & its perfect again

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Is it possible the bridge posts are being pulled out of alignment? I've seen taht before, not common, but I had a 540r that had a bridge post pull "forward", and it wouldnt intonate. I just wound up doweling it with some oversize maple and redrilled the whole, worked fine after that...

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Is it possible the bridge posts are being pulled out of alignment? I've seen taht before, not common, but I had a 540r that had a bridge post pull "forward", and it wouldnt intonate. I just wound up doweling it with some oversize maple and redrilled the whole, worked fine after that...

The guys tech taught of that before, The post sleeve was moving up & down in the body at one time. But he epoxied it into place years ago. It was one of the things I checked when I replaced the studs & bridge anyway.

If it was a basswood body id suspect post movement to be a problem again as that is quite a soft timber. But this is an alder body Jem.

I dunno :blink:

Anyway, I spoke with the owner today. It has another neck to go with it, (there were 2 more necks than guitars left in to me) He sometimes swaps out the ebony boarded JEM7 neck for a 555 neck with a rosewood board. I refretted that today, Im gonna swap them over tomorrow & im wondering if the occasional swapping of necks is having an effect. Its not like its only had its neck swapped out once in its life, it happens 2-3 times a year & hes been doing it for about 7 years at this point.

They tell me that for a while this was happening during gigs. he might just get an urge to have a maple or rosewood board. A neck would be sitting offstage already strung up with the bridge attached. They would just pop the trem srpings, unbolt the neck & swap it out for another one - bridge, nut, tuners, strings all in one. bolt on the new neck & tension it all up in a few minits.

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hmm, have you thought of a vertical shim? Instead of shimming the angle, put a peice of stock in the base of the neck pocket where the neck heel meets the vertical part. If he's swapping necks a lot, it could be very possible stuff is simply worn out and needs more room. May seem silly and nonsensical to even suggest, but I'd check the exact scale length with a high quality straight edge, make sure everything is lined up as it should be. If its not, you can find out pretty easily at which part its "wrong".

If they are epoxying the hole, it may be worth while to dowel and redrill it anyway! :P

Edited by bob123
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the only thing that comes to my mind would get 2 strings to consistently NOT be able to get intonated is some problem with the nut - as already suggested. Maybe the slots on the locking nut are worn in some weird way making the final point of contact with the string move a little towards the headstock?

I don't think so, I've owned about 100 different ibanez guitars. the pads wear out long before the nut will. besides, the nut being too low would make intonation BETTER, albeit probly cause some buzzing. If it were moving forward as you're thinking thats still easily in the range of the floyd rose to intonate into.

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Pan-kara, I replaced the bridge, posts & nut. So no wear to contend with.

Tim37, yea, similar issue with any neck they use.

But i am getting somewhere with this now.

I took off the Jem 7 neck to try the 555 & found a few issues.

The body:

01) the screw holes are mis-shapen, oblonged & over sized.

02) the small section at the back of the neck pocket between the heel & pickup, is broken away on the treble side.

03) the floor of the neck cavity is uneven, it has a very slight dip in the area of the rear treble screw hole.

04) lastly, there is what appears to be a hairline fracture sarting to run up the body from the treble side screw hole all the way to the back of the bridge pickup cavity.

Jem 7 neck:

The screw under the 23rd fret- treble side, there is about 4mm of screw tip snapped off & permanently stuck in the neck. so only part of that screw is actualy gripping the neck when its installed.

(kinda explains why they did not want the neck removed for the refret)

I tried the 7 & 555 necks in one of my own bodies with the original hardware form the white jem. No issues at all, no matter how abusive I was with the trem arm. I contacted the player & explained what I wanted to do & got the go ahead - so.

I sprayed some steel rods with teflon, positioned them in the body screw holes with a jig & flooded the holes with epoxy.

Flooded the fracture in the body with some realy thin CA.

Then I leveled the neck cavity floor & shimed it with some ebony.

Drilled out the broken neck screw (always fun)

Clean it all up tomorrow & see how it goes from there.

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Good luck btw build them a couple of bodies for the other necks and tell them to stop the swaping bs.

Wouldnt help. hes a serial tinkerer. likes to tweak some of his gitirs, & others just turn into experiment labs. Its not like he has not got any to spare, he's just a bit "out there" you know.

I might just give him 2 bodies for the other necks, Im building him a new JEM anyway. So throwing in 2 test mules I have here wont kill me. Especialy since one of them is loaded with his 555 neck & original hardware already.

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OK. This is a giant pain in the ass.

I had to level & then shim the heel of the 555 neck as it was a little compressed/rounded towards the end. So it did not have a flat face.

Tried it on one of my own bodies & it was perfect after the work.

Apart from the damaged screw the 7 neck seemd fine. tried it on the same body & it was fine.

Then I got the body sorted. Neck pocket cleaned up & leveled, screw holes cleaned up, crack sorted. The 555 neck is on there & it intonates perfectly. Even after some major trem abuse.

But the 7 neck would not stay intonated when on the original JEM7wvh body. Although it was fine on one of my own bodies with its old hardware earlier, & is fine on there again now.

I have notaiced that it is thinned on one corner of the heel on the treble side. 0.02mm off of level with the rest of the heel tapering back about 1/4 of the way to the front 2 screw holes.

Im wondering if I should shave back the base of the 7 necks heel. then shim it. Just to be sure. Waiting for the customer to get back to me on it.

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