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Need a tone control. Help?

Discussion in 'Pickups & Electronics [BG]' started by Official Ninja, Aug 15, 2012.


  1. Official Ninja

    Official Ninja

    Oct 21, 2009
    New Jersey
    My Yamaha RBX-170 needs a new tone control. I don't know what happened but it looks like the tone knob may have taken a hit because the knob spins "wobbly" and the control seems to have no effect on the sound.

    I opened it up and looked. It is a pretty small pot in there.
    I have no idea what I should get to replace it.
    I'm looking for information on the subject and links to online stores that would have a suitable replacement.

    I've never had to replace any electronics in my basses before.

    Thanks!
     
  2. DiabolusInMusic

    DiabolusInMusic Functionless Art is Merely Tolerated Vandalism Supporting Member

    Is the pot still connected properly and not functioning or have one or all of the wires been detached?

    If it has actually failed, you can easily obtain a replacement pot from an electronics supply place or most music stores if they have a repair guy.

    If your comfortable with a soldering iron it is a very easy fix/replace, if not, spend 30 minutes practicing soldering wires to tine cans and you should have enough experience to tackle the job.
     
  3. Official Ninja

    Official Ninja

    Oct 21, 2009
    New Jersey
    The wires are still hooked up. The pot itself is broken. I'll have no problem doing the soldering.

    I have no idea what I need to get though.. like what value is pot?
     
  4. bumperbass

    bumperbass Supporting Member

    Jun 19, 2012
    It should have the value printed on the pot, such as 250KJ, or something like that. Is it a mini control?
    "Yamaha 24x7

    In order to use the Yamaha 24x7 parts order website, you will need to know the Yamaha part number(s) you would like to order. If you do not know your part number(s), please contact us for assistance by dialing (888) 892-6242, Monday through Friday, from 7:30AM - 5:00PM Pacific Time (closed 12PM - 1PM)."
     
  5. bumperbass

    bumperbass Supporting Member

    Jun 19, 2012
    I have the service manual for an RBX170. It's a 250K audio pot; the same value that's in a Fender Precision/Jazz and a million other basses. Just buy one that'll fit your knob, depending on if it's a split or solid shaft. I don't know that information.
    The Yamaha part number is HS120100. Good luck.
     
  6. Official Ninja

    Official Ninja

    Oct 21, 2009
    New Jersey
  7. bumperbass

    bumperbass Supporting Member

    Jun 19, 2012
    Good deal. I bookmarked the page. Can't have too many choices for parts sources.
     
  8. Official Ninja

    Official Ninja

    Oct 21, 2009
    New Jersey
    Ok, I received the new tone control and installed it. The bass still works :)
    However, the tone knob still does nothing. Does this mean the resistor in there is no good?
    What is the value of the resistor. What value should it be?

    Thanks.
     
  9. SGD Lutherie

    SGD Lutherie Banned Commercial User

    Aug 21, 2008
    Bloomfield, NJ
    Owner, SGD Music Products
    You mean capacitor. What cap was on the old potentiometer?

    How did you wire up the tone control?
     
  10. Official Ninja

    Official Ninja

    Oct 21, 2009
    New Jersey
    Black wires to one side of cap. Other side of cap to center pole on tone control. Red wire to right post looking at the bottom, poles down.
    That is how it was wired, I just moved everything to the new pot.

    It looks like cap says 100uf on it, but it is hard to see.
     
  11. Official Ninja

    Official Ninja

    Oct 21, 2009
    New Jersey
    I got it working. The effect it makes is very very little. I remember the tone control having more of an effect on the sound. Now it just cuts the treble out very slightly.

    Is there a way to make it cut out more?
     
  12. bumperbass

    bumperbass Supporting Member

    Jun 19, 2012
    Here's the diagram attached. Good luck.
     

    Attached Files:

  13. Official Ninja

    Official Ninja

    Oct 21, 2009
    New Jersey
    Thanks. I think it is working properly. I took out my BB414 and it seems the tone knob on that bass has about the same effect.

    I don't have my big combo amp right now. I'm using a little 20w Hartke. Maybe that has something to do with my not hearing a big difference from moving the tone knobs on these basses.
     

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