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JTV59 intonation cant be fixed?


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I bought a JTV59 used about a year ago, beautiful guitar, and I love the tone options available, but it's never played properly in tune. The high E and B are always flat at the 12th fret, and there isn't enough range on the individual saddle adjustments to bring them closer to the neck, which would be required to sharpen them up a bit.

I decided to have a closer look, so I removed the strings, and the two little set screws at the back of the bridge that adjust the bridge position against the bridge height adjustment screws. The set screw for the treble side was backed off pretty much all the way, allowing the bridge to be as close to the neck as possible. Also, I found the bridge really hard to remove unless you alternately adjust the bridge height screws slightly till the bridge stops binding on the screws.

Having removed the bridge (masking tape on the guitar body, and careful not to damage the wires under the bridge for the piezo saddles) , I could see that there is pulley shaped bearing wheel at the top of the bridge height adjustment screw, and this v grooved wheel fits inside the bridge, one at each side. The little set screw at the back of each side of the bridge determines the coarse intonation of the bridge (fine adjustment being done by the individual saddles).

Clearly the bridge height screws have been improperly positioned on this guitar, and the only way i can think of to solve this problem is :

a) relocate the bridge support ferrule(s) slightly which would be a major task, and would leave marks on the guitar.

b) machine down the little pulley at the top of the support pins. I tried this  by putting the support pin in a drill and running it against an abrasive, but it barely made a mark.

Anybody else have this problem, or have any other thoughts?

20210204_163756.jpg

20210204_163812.jpg

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2 hours ago, oldmanrockband said:

I bought a JTV59 used about a year ago, beautiful guitar, and I love the tone options available, but it's never played properly in tune. The high E and B are always flat at the 12th fret, and there isn't enough range on the individual saddle adjustments to bring them closer to the neck, which would be required to sharpen them up a bit.

I decided to have a closer look, so I removed the strings, and the two little set screws at the back of the bridge that adjust the bridge position against the bridge height adjustment screws. The set screw for the treble side was backed off pretty much all the way, allowing the bridge to be as close to the neck as possible. Also, I found the bridge really hard to remove unless you alternately adjust the bridge height screws slightly till the bridge stops binding on the screws.

Having removed the bridge (masking tape on the guitar body, and careful not to damage the wires under the bridge for the piezo saddles) , I could see that there is pulley shaped bearing wheel at the top of the bridge height adjustment screw, and this v grooved wheel fits inside the bridge, one at each side. The little set screw at the back of each side of the bridge determines the coarse intonation of the bridge (fine adjustment being done by the individual saddles).

Clearly the bridge height screws have been improperly positioned on this guitar, and the only way i can think of to solve this problem is :

a) relocate the bridge support ferrule(s) slightly which would be a major task, and would leave marks on the guitar.

b) machine down the little pulley at the top of the support pins. I tried this  by putting the support pin in a drill and running it against an abrasive, but it barely made a mark.

Anybody else have this problem, or have any other thoughts?

20210204_163756.jpg

20210204_163812.jpg

 

Silly question... Can you try some different strings?  Maybe the ones that you have used could be of a bad batch?  Just a thought.

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Check your pickup height. If they're too close to the strings, intonation problems can sometimes result. It tends to be more of a problem with single coils, but a magnet is a magnet... too close and it can push you out of tune just enough that it makes intonating some strings difficult, if not impossible.

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oldmanrockband,...

The solution is the two bridge coarse adjust screws, there is a slightly longer version by 1.5mm of those.

I don't have any myself. Check with Full Compass, Long & McQuade or Yorkville to see if they have any or

can order a pair for you.

 

crusinon2 has a good point, so good to check that. Depress the highest fret on the lo-E string, the pick-up

to string distance should be 3mm. Do the same on the hi-E side, distance between pick-up and string should be 2mm.

 

 

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On 2/5/2021 at 12:15 PM, psarkissian said:

oldmanrockband,...

The solution is the two bridge coarse adjust screws, there is a slightly longer version by 1.5mm of those.

I don't have any myself. Check with Full Compass, Long & McQuade or Yorkville to see if they have any or

can order a pair for you.

 

I thought I replied to this, but I guess it didn't take. Yeah. that would work if my problem was the other way. i.e. If intonation was  sharp at 12th fret and i needed to move the bridge closer to the guitar endpin. I did see another post on this and the longer screws would work in that case. I might bite the bullet and remove the ferrule, plug the hole and relocate the ferrule about 4-5 mm towards the fretboard, but because of the close tolerance between the bridge height adjustment screws and bridge itself, I may have to move both ferrules to avoid binding.

 

 

 

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oldmanrockband,...

Don't do that, don't do any mod's, that would be an unsupported mod.  The longer version coarse adjust screws

allow more leeway for adjusting the bridge so that finer adjustments can be made at the piezo level.

 

Log support ticket in your account, they can refer you to an authorized service center for guitar work. Yorkville in

Pickering has a guy there that trained with us here. And they have access to me through service center channels

for further consulting if they want.

 

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1 hour ago, psarkissian said:

The longer version coarse adjust screws

allow more leeway for adjusting the bridge so that finer adjustments can be made at the piezo level.

 

 

 

No, they don't. They only allow the bridge to be pushed further away from the pickup, which is not helpful in this case.

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1 hour ago, psarkissian said:

Something else in the set-up is going on there, maybe relief. Using 10-46 gauge string sets?

 

Contact Mark Wright about it, he'll know how to deal with it. And he can pick my brain, as we

stay in touch, us being long time mates and all.

 

 

Thanks; I use 9-42's, and  I do know that heavier strings will help somewhat, but that's not a good solution for me  IMHO. I'm not sure who Mark Wright is, but I'd love to pick his brain! This particular Variax is 314 mm from the middle of the  12th fret to the middle of the saddle. (max adjustment, towards the neck) My other Variax intonation is spot on with the 'E' saddle at max adjustment with 312 mm measured the same way.. 

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Problem solved! I reattached the bridge and restrung the guitar. I also set up the action. Originally, I had 314 mm from twelfth fret to the bridge saddle, now it's 312.5 mm. My suspicion is that the bridge was binding on the bridge height adjustment posts on the high 'E' side and wasn't  as close to the neck as it could be. The bridge does bind if the support posts are not equal, as I found out when I tried to remove it. It's still at maximum travel, but within tolerance. Case closed!

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1 hour ago, psarkissian said:

"Binding,... that could be, if one side is much higher than the other."

Now that I think about it, it was definitely binding. Referring to my original post, I couldn't remove the bridge after taking off the strings, until I adjusted one of the bridge height adjustment screws. Good to know for others who may have a similar problem!

 

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