4003 neck - can´t get it straight

[mikko]

This issue is probably already discussed somewhere on this forum but because I couldn´t find it, here it comes again…

I have a -03 4003JG bass. When I play on 10th fret on A-string and on 11th fret on D-string simultaneously, the A-string heavily buzz between 1st and 10th fret. That does not come out of the amplifier but I can hear it when playing and that´s annoying. I checked the neck with ruler and it was bowed. I tightened the truss rods (1/8 turn per day) and it got better. After certain point neck started to backbow from 3rd fret (between nut and 3rd fret). When I tightened the trussrods more (something like 1/12 turn) backbow started from 4th fret so I loosened the trussrods until backbow was gone. Now neck is still bowed and I can´t tighten the trussrods or otherwise the neck will be more or less S-shaped. What should I do now?

[jps]

Check for a high fret that the A string may be hitting. My former Fender AV '62 Jazz Bass had a similar problem when I played a certain double stop, B♭ on the E string along with the D on the G string (a major 10th). My solution was to just use my index finger to mute the E string below the fretted note.

[johnallg]

Check to see if the backbow on the truss rod has flipped 180 degrees..... I've experienced this twice and had the same symptoms you relate.

[mikko]

Check to see if the backbow on the truss rod has flipped 180 degrees..... I've experienced this twice and had the same symptoms you relate.

Sounds worth trying….since I´m not very experienced with different kinds of setup/repair procedures, I think it´s better to ask before doing something stupid.
Should I take the strings off and loose the truss rods completely. Then remove the pick guard and take truss rods out and check if they have turned 180°. Then put them back the right way, tighten the truss rods nuts by fingers, strings back (in tune) and then tighten the truss rods until neck is straight?

[grazioso]

i am assuming you are using normal gauge of strings and not something exotic....
i'd try complete reset of the setup first: take off the string tension and loosen the rod nuts all the way - no tension on rods or neck, put the bass in its case for a day or two with humidifier, than check the neck with straight edge for high frets and twists...if that is ok start with the setup over...it will help if you use old method for setup - the one for 4001, it won't hurt the neck if it gets help to get in the desired position before you snug up the nuts on rods.

[mikko]

i am assuming you are using normal gauge of strings and not something exotic....

.045 -.105 DR Low Riders

i'd try complete reset of the setup first: take off the string tension and loosen the rod nuts all the way - no tension on rods or neck, put the bass in its case for a day or two with humidifier, than check the neck with straight edge for high frets and twists...if that is ok start with the setup over...it will help if you use old method for setup - the one for 4001, it won't hurt the neck if it gets help to get in the desired position before you snug up the nuts on rods.

I actually tried the neck reset already. Without strings and truss rods completely loosened the neck had some bow. The bow radius looked constant and there was no twist. I haven't tried the old method yet but I'm definitely going to try it next, before taking the truss rods out.

[MyBBruce]

All you need to do is Tune to pitch than get the neck close but with some minor relief than start a little twist every other day. Keep in mind both Rod don't need to be the same. A back bow on the Bass side may not come out 100% with just the bass side adjustment. Getting the neck straight has a lot to do with patience and Feel and an occasional straight edge check. If you try to make it perfect in a day or 2 it will never happen. If you think the nuts are to tight they probably are.

Not sure how dry it is in your home or where the guitar is most of the time. That can make a big difference. 46 % is perfect humidity. If your at 40-45 05 47 -50 your still ok anything above 50% of Below 40% to bad. I"ve had guys say that doesn't matter but it does. That's what a truss Rod helps with.

Good luck. You'll know when it's right. It will play really smooth.

[mikko]

Problem solved. It just took some time. Maybe humidity also played some role in this case, it´s just around 30% in my apartment in winter time.