Repair non-functioning pickup?

Discussion in 'Pickups & Electronics [BG]' started by Sundogue, Jul 5, 2013.


  1. Sundogue

    Sundogue Supporting Member

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    I have a Yamaha BB415 and the Jazz pup leads were broken when it was removed. I tried resoldering those thin little wires back to the wires (that go back to the pot) but it still does not work.

    It has the thinnest little wires coming off the pickup itself. I thought the bobbin was metal, not plastic (me being dumb) and I melted the plastic where they were originally attached (two little holes where the wires and leads meet at a solder joint). I managed to solder the leads back together a little further up.

    The pickup sounds just like the other (working) P-Bass pup in that when I connect the leads to a 1/4" plug and plug it into an amp, when I tap on the pup with a screwdriver I can hear the tapping audibly through headphones. Yet when installed and playing the bass strings, there is no output whatsoever.

    Any ideas?
     
  2. Sundogue

    Sundogue Supporting Member

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    After further reading, it may be that the tiny, thin coil wires have a coating on them that needs to be removed before re-soldering them to the leads. I may have soldered them together without removing the coating, so perhaps there isn't sufficient contact in the connection.

    Make sense?
     
  3. mech

    mech

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    Normally, the heat of soldering is enough to burn the insulation off the coil wire. If the pickup works when not connected to the bass wiring then something is wrong with the wiring in the bass or the way the pickup is wired in. Good pics would help.

    mech
     
  4. Sundogue

    Sundogue Supporting Member

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    Well, I took it all apart after much reading, and unwound about 3 wraps of the coil wire and found a broken section.

    I carefully soldered up the connections, put it in the bass and tried it again. It works now. I do get audible sound from my strings through that pickup now.

    However the output is incredibly weak. I only unwound the wire about 3 times. That's not a significant amount to change the output. Something else is wrong with it but damned if I know what it is.

    It is NOT the rest of the wiring or controls. That's all been tested (wired the P-bass pup to the Jazz pup control and all is well there). It's something in the pickup. Sound is now there, but it's WEAK. Ugh. Damn, I really loved both the P-Bass and Jazz pups of my Yamaha. Killer sound. Used to anyway. P-Bass pup still sounds great with lots of output.
     
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  6. GlennW

    GlennW Supporting Member

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    I'll guess you didn't strip the insulation from the coil wire before soldering. You're lucky to be getting any sound, but I'd also guess the heat from soldering melted enough of the insulation to give you a poor/weak connection, which is why you're getting any signal at all.

    I could be wrong, but that's my guess.

    Did you strip the insulation prior to soldering?

    Did you get a DCR reading before soldering it back in? If yes, what was it?
     
  7. Sundogue

    Sundogue Supporting Member

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    Yes, I carefully sanded the thin coil wires (with 600 paper) per the recommendations of some sites. Just wrapped and ran the paper down each wire a few times. Any time I tried to scrape it like with a new Exacto blade it just cut too easily.

    I did not take a reading at all. I figured it either works or doesn't.

    I'm thinking I might just get a used jazz pup (not a Yamaha). I found one online that when the pup cover is removed, fits inside the Yamaha Jazz pup cover and the pole pieces line up with my strings by the bridge. The only thing is, the Yamaha pup is a a blade style and the Jazz one is the standard Jazz pup with individual pole pieces, so the cover will expose the parts between the poles. No biggee I guess.

    Not easy finding a used 5 string BB415 Yamaha Jazz pup.
     
  8. GlennW

    GlennW Supporting Member

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    I'm unfamiliar with your pickup and how it's made.

    You say it's a "blade style." Is this blade the magnet, or is there a bar magnet on the bottom of the pickup which contacts the blade?

    If there's a bar magnet on the bottom, it might be sideways. That would cause a severe loss of output. IOW, the north or south side of the bar magnet is NOT contacting the blade.

    Is the magnet positioned now the same as it was when the pickup had good output, or has it been repositioned?
     
  9. Sundogue

    Sundogue Supporting Member

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    There is a bar magnet on the bottom and a blade on top. The magnet runs the entire length of the pickup, as does the blade. Those components haven't ever moved. They've always been very solid as if they were one piece. The only thing that has ever gone wrong is the leads coming off from too many installs/removals (I've built different bodies and also have repainted this Yamaha body a couple of times, so the pups have come in and out many times). I should have taped the connections down tight, but never thought they'd come loose.

    So in an attempt to resolder the coil wires to the leads into the holes on the housing, the damned housing melted so I've had to tape the leads to it.

    Damn, I'm really not digging having to pull it out and make damned sure those coil wires are "stripped" good enough. They are so freaking fragile as it is. But I guess I'll have to give it one more go and make sure there is perfect contact.

    I went from NO output to a little output, so I guess the pickup still functions.

    How do I go about taking a reading with my meter? What do I set it to and where to take the reading from?

    Thanks for your help.
     
  10. GlennW

    GlennW Supporting Member

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    No output to some output is progress, and a good sign.

    Set your meter to 20kOhms. You can take a reading at the ends of the leads. If it's still soldered in turn the pots to 10. That won't give you a "true" reading, but it'll be close enough to let you know if it's any good. If you don't get a reading on the 20k scale, try the next higher up. Most pickups will read on the 20k scale, but very hot ones like the Guild, Gibson, and Fender humbuckers won't because they have a lot more resistance.

    You can also try to get a reading at the lead-to-pickup connection, but be careful not to break the wire.
     
  11. Sundogue

    Sundogue Supporting Member

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    Ugh! took it all apart and made sure the coil wires were stripped and re-soldered it again. Put it all together and...NOTHING. Back to no output again. Sigh. What a pain.

    I might just give up and get a different Jazz pup and do what I can to retrofit a real Jazz pup into the Yamaha. Sucks mostly because that Yamaha Jazz pup (as well as the P-Bass) were really HOT pickups for being passive.
     
  12. GlennW

    GlennW Supporting Member

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    You might have another break in the coil wire somewhere.

    If you try it again, check with the meter BEFORE soldering. One probe on the good lead, one probe on the freshly stripped coil wire. That'll tell you whether or not you have anything worth soldering, or whether you have more work to do.

    Edit: Also check with the meter from the blade to each lead, one at a time. The wire might be shorted to the blade at the inside of the coil, in which case yer screwed.
     
  13. Sundogue

    Sundogue Supporting Member

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    Thanks, I will check with the meter first.
     
  14. Sundogue

    Sundogue Supporting Member

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    I checked it with a meter. Nothing. Then re-soldered it one more time and got it to work again, but the reading is very low. Output is very low and it's just not worth using.

    Something is shot in the pickup. Oh well. I'll just have to find a suitable J replacement as I don't want to mess with it any longer.

    I learned a lot in this experiment. First off, when removing pickups, make sure the damned leads are secured (tape them down or something). Second, don't let it get to the point that I have mess with the thin coil wires in the first place.

    I don't know how people who make pickups can even deal with those tiny wires. Ugh!

    Thanks so much for the help anyway. I really appreciate it!
     
  15. GlennW

    GlennW Supporting Member

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    It sounds like a case of self-capacitance. That's when the pickup is dead, but it doesn't know it. There might be another break in the wire, and just enough signal is making the jump to almost work.

    I'd peel more winds for a while to see if there's another break, but if you're fed up with it I understand. It's tedious and delicate work.

    Again, if you get a reading other than "open line" across either lead and the blade it's a lost cause.
     
  16. godofthunder59

    godofthunder59 Supporting Member

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    Why not contact Yamaha for a replacement?
     
  17. 4Mal

    4Mal Supporting Member

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  18. Sundogue

    Sundogue Supporting Member

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    So what's a rewind cost?

    I'm thinking I'd almost rather get a 5 string Jazz pup and retrofit it in there. Not all that hard to do. Yamaha uses plates around the pups anyway so it would be easy enough to make a new plate to hide anything not fitting the hole properly.

    Don't have a lot (read as, none really) of cash to throw at it, so I'm looking at a used, cheap 5 string Jazz pup to replace it.

    Anyone know where some used Jazz pups can be had really cheap? Checked classifieds and ebay already. Found a few that might do the trick. < $30 but don't even have that spare right now.
     
  19. Sundogue

    Sundogue Supporting Member

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    This is the bass the pickup is in (which is disconnected now). I'll find a replacement or get it rewound someday. Still sounds fabulous with even just the P-Bass pup, but I do miss the Jazz for some things.

    [​IMG]

    [​IMG]
     
  20. walterw

    walterw Supportive Fender Gold Supporting Member

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    nice bass, but i doubt anything besides a stock replacement would fit without a bunch of surgery.

    you probably had a busted coil wire the entire time; it'll still make sound, especially when you tap it with a screwdriver, but will have very weak output.

    measuring it with a meter will show resistance in the hundreds of k- or even M&#937;.
     
  21. Sundogue

    Sundogue Supporting Member

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    I found a Jazz pup that when the cover is removed will fit inside the Yamaha Jazz cover. The screw down ears on the Jazz pup are only on the cover and the pickup itself fits nicely in the Yammy cover. The only difference cosmetically is that the Yammy cover is for a blade and the Jazz replacement has separate pole pieces so the cover will be open across the pole pieces and in between them. No big deal.
     

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