Need assistance with Bronco re-wiring.

Discussion in 'Pickups & Electronics [BG]' started by Outtaseezun, Jan 8, 2022.

  1. Dear Fellaz & Fellazettes,

    This is my second time ever trying to fix/upgrade a bass guitar. First time was a Jim Harley Precision Bass & it worked out okay.

    But this time, i tried to upgrade pots (500K), cap (0.047mfd) & jack, as well as replacing the pick-up with a MusicLily Dual Rail. Had to do a bit of research because there were five wires: red, black that was soldered to a bare one, white that was soldered to a green one. I thought that red was the hot wire, soldered now to the right leg of the volume pot, that the black/bare was the ground, now soldered to the back of the volume pot, and that since i wasn't going to split, green/white should just be isolated from the circuit together.

    I thought i was done with all the soldering so i put the bass back together aaaand... well it doesn't work.
    Basically, the notes i play sound like super distant farts. I brought the pick-up closer to the strings so it got slightly louder but still unusable.

    My soldering iron is probably crap, had a wait a lot for parts to heat up before i would tin them. Apart from that, i don't know what i did wrong. I am attaching pictures. Please forgive the horrible soldering...

    What should i do, if U have a spare minute, please ?

    20220108_155721.jpg 20220108_155727.jpg 20220108_155746.jpg 20220108_155804.jpg
  2. jallenbass

    jallenbass Supporting Member Commercial User

    May 17, 2005
    Bend, Oregon
    Have you tried the old pickup with those controls just to be sure that it's not the new pickup that is causing the problem?
    lark_z likes this.
  3. It looks like a leg of the capacitor is touching the back of the potentiometer. That will cause the tone control to act like a second volume and affect the overall sound.

    You should also check if the output jack is touching any shielding in the control cavity.

    I can’t really see it but I’m not sure about the solder connection for the red wire at the volume pot also.

    Other then that, the only thing I’ve got is if, as you say, you had to hold the iron on components for a long time to heat them up something could have gotten fried, maybe the volume pot but check the capacitor and output jack first.
    lark_z and Rich Pearson like this.
  4. Hello @jallenbass !
    Thanks for suggesting that. I will try that as soon as i get confirmation i did everything else correctly. Trying to avoid multiple unsoldering, soldering, unsoldering again etc..
    But if other members confirm my wiring is correct then i'll definitely try that! Thanks!
  5. Hello @Matt Liebenau !

    So i just moved the leg of the capacitor away from the tone pot, it was indeed touching.
    The output jack is not touching the shielding in side the cavity, but it is indeed touching where it is screwed to the pickguard... but there was some aluminium shielding there before i put copper & it didn't affect the sound.

    Here are some more pics:
    20220108_171429.jpg 20220108_171442.jpg 20220108_171511.jpg
  6. Was the insulation on the jumper wire between the volume and tone pots ok before you soldered the new pickup in? If so and that melted from the soldering a pot could have gotten screwed up.

    On the output jack, the body is supposed to touch the pickguard, that’s how some companies (Fender) ground them even though it’s not best practice. I meant the long leg part that’s below it. That moves slightly when a plug is inserted and if it’s close enough to a cavity wall could touch the shielding enough to cause a partial short.

    Did the problem get any better when you moved the capacitor leg?

  7. Yeah, that wire was wrapped in cream coloured fabric. Cutting that little bit of wire made the fabric go messy so i removed it, but some might have melted when i soldered.. so that could be it.

    Okay i got the part about the output jack, thanks. And yeah the leg that touches the male jack when it's inserted doesn't touch the shielding at all inside the body of the bass. There is a good half centimeter of distance when the pickguard is on the bass. I measured.

    Yes, removing the leg did solve a pronlemi hadn't noticed before U mentioned it. The tone pot was indeed acting like a 2nd volume pot. So that has been solved thanks to you!
    Matt Liebenau likes this.
  8. Is the original problem still present? If so and you don’t have a multimeter to test with you may have to resort to testing one thing at a time. In other words, hook the pickup directly to the output jack and check. If it sounds good add one component at a time until the problem returns and that component was the issue. The good thing is that it’s a pretty simple circuit so there’s not too much to test.
  9. Hey @Matt Liebenau ,
    Thanks a lot for asking. I had to do other things after my last post, & i abandoned the gutted bass, belly up, like the victim of some sordid crime...

    I do have a multimeter actually! How should i use it to see where the problem is?
    My initial concern was that i might have misunderstood the colour-code of the pick-up wires... but there is a signal. If i had miswired the whole thing, i would get any notes, right? Cuz even if they are distant & sound like farts, i can hear the notes i fret in there...

    Maybe the multimeter trick will be enough, if you'd be kind enough to tell me how to use it? Or maybe tell me what i should type online to find the right tutorial for my needs?

    Thanks a lot again for asking, super kind of you!
  10. Hmmm… you’ll have to disconnect some things for a proper check. You want the meter on ohms. If you have to select a range whatever is around 20K will work. One thing you can do is check the wire connections. Read from the back of each pot to the ground connection on the output jack. For that you can use the lowest ohm setting and 0 is ideal. Not more then a couple of ohms. After that follow the hot connections. Read from the red wire on the volume pot to the now bare wire connection on the tone pot then from the white wire on the middle tab of the volume pot to the output jack. Again, more then a couple of ohms is too much.

    After that, go back to the 20K setting. You’ll have to disconnect the pickup and if you read across the red and black I’d expect 7-15K ohms. You can also check the pots. The two outside terminals should read the stated value, 250K or 500K ohms (you’ll have to change the meter setting) typically +/- 10%.

    I just thought of this, before all that, have you plugged into an amp with the pickguard off of the body? I know you said the jack is ok but if something else is touching the shielding it should be ok with the guard off.
  11. andare


    Oct 4, 2016
    Your solder joints are pretty messy. Make sure there are no strands making contact where they shouldn't. When you strip a wire you should twist the strands together and then apply solder to them so they stay together. Like this:

    Are you sure you've wired up the pickup correctly? Those dual rail humbuckers usually have 5 wires. The bare wire always goes to ground (back of vol pot). Two of the wires are soldered together and taped off, one of the remaining wires goes to ground and the remaining one goes to output (lug 3 of vol pot). That wires it in series. The wires are always white, red, black and green but they don't match across manufacturers.

    Have a look at these:

    Artec-4_conductor_wiring.jpeg bucLvlA.jpg
    NathOBX likes this.
  12. Hello @Matt Liebenau & @andare !

    Reporting from the front:
    I tried connecting to my combo the whole set up on the pickguard without the body of the bass, lowered the volume of the amp to not blow it up and put an allen key to the blades of the dual rail. There was that clank noise followed by static but still super low volume, like in the distance. I tried at different volumes & reached 75% of my amp volume knob with still very low output.

    So i checked all my wirings & they all came back with between 0 & 3 ohms.
    I also checked both pots using the outside terminals & both read 460-470K.
    I unsoldered the pick up, set the multimeter on 20K and got:
    - nothing at all between red & black&bare
    - 4.88 between black&bare & green&white
    - 4.89 between white alone & red
    - 4.88 between black&bare & green alone

    All the other combinations show 0.

    When i first got the pick-up green and white were soldered together.
    Here is the diagram that comes with it:
    I was using the "Humbucker" diagram, folded white & green (unsoldered & didn't make contact, maybe that was my mistake ?) out of the circuit, used red as hot & black&bare as ground...

    They say it's a 9Kohms pick-up... i got ripped off didn't i?
  13. Okay guys,
    I think i might have figured it out: i used white&green soldered together as hot & didn't use the red wire.. i think it works now. Am gonna try with strings on & will report back soon!
    Thanks for Ur help!
  14. T-34

    T-34 Wanna go headless? Supporting Member

    Yeah, you need to solder green and white together and tape this off, then your black and bare will go to the ground and red to the pot's lug as "hot".
    andare and lark_z like this.
  15. In post 12 you said white and green were just out of the way and not making contact. If you want a humbucker you need to strip and solder white and green together then heat shrink or tape them off so they don’t make contact with anything. That’s why you were getting an open circuit across red and black. If you connect white and green you should read 9-10K ohm across red and black and it should work normally.

    And yes, when you put it back together you’d benefit from some neater solder joints.
  16. Oh... i guess i shaged up.
    I did what i said in post #13 & the bass now works, no undesired noises, normal volume and all... but apparently i didn't do it right, did i? Red is indeed hot. What do i have now basically? A single coil?
  17. I’m not sure what you have hooked up. If white and green are connected as hot and black is ground then it’s set up as a single coil. If red is hot and white and green are on ground, again single coil. Red hot, black and bare ground and white green soldered together is humbucker.

    The only other thing that would work is red and green to the hot on the volume and white, black and bare to ground would be a parallel humbucker. Looking at your ohm readings I think that’s right I might have green and white backwards.
    Outtaseezun likes this.
  18. Got it! So for now it's single coil!
    I'll open it up again probably on Wednesday & rewire to humbucker! I have a lot on my plate on Monday & Tuesday...
    Thanks a billion times for Ur assistance throughout the whole process! Much appreciated!!!
    I will post pics & maybe video link when am done!
    T-34 and Matt Liebenau like this.
  19. You’re welcome. When you’re really feeling adventurous switches can be added to switch some of those options in and out.
    Outtaseezun likes this.
  20. HAHAHAHA yeah, i'll try & recover from the "***-have-i-done" trauma & probably experiment a couple of years looool
    Matt Liebenau likes this.
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