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yamaha bb1500a blend pot issues.. replacement?

Discussion in 'Pickups & Electronics [BG]' started by bass349, Aug 30, 2007.


  1. hi guys,

    i'm having some issues with the blend pot on my yamaha bb1500a. It's only started recently, but the pot seems to be on the go. sometimes my bass will start to lightly distort.. or i get a slight volume cut. i've narrowed it down to the blend pot, because when it's happening if i press down on the pot or wiggle it around a bit it seems to make it go away.

    i had a quick look in the control cavity, and it seems the pots are directly connected to the pcb board. i've never really seen that before. possibly the problem is coming from a connection problem from the pot to the board??

    i've tightened the nut on the pot, and that made it go away for a while, but unfortunately it's come back. and i don't think i can tighten that nut anymore!

    so, i need some advice here. i was thinking i should just replace the pot.. but because it's connected to that board, i'm not so confident in replacing it myself anymore (i'm happy soldering, and done a few electronics mods and such.. but i don't want to screw anything up). So not sure if thats my best option.. and even if i go down this angle, i have no idea what value that pot is, and i'd probably have to order from the net as i've looked for those kinda parts around here before to no avail.

    so to summarise my ramblings.. i'm needing help on a few matters;

    - does anybody know what value pot i would need buy as a replacement?
    - how hard is it to replace pots that are directly soldered to the pcb board? and any advice if i go down this angle?
    - do you think the problem might simply be a connection problem, not a pot fault?

    thanks guys i muchly appreciate in advance your collective advice!

    all the best,
    andy.
     
  2. luknfur

    luknfur

    Jan 14, 2004
    DIXIE
    FWIW:

    I would plan on replacing the pre. With that approach, you really have nothing to loose by messing up the existing pre if you're up for the challenge or want to bother. Trouble shooting PCB's is no beginner project. You would need some solder wick/solder sucker cause you have to actually remove the solder not just heat it up on those PCB's to get the pot seperated.

    I would also replace the battery, a blend isn't going to cause distortion.
     
  3. hey, cheers for the advice.

    hmm. a slightly more expensive sollution than what i was hoping for. the battery is not a problem.. as i mentioned, when you wiggle the blend knob the distortion goes away. I have a feeling that it is a connection problem.. just has that sound about it to my ears. maybe from the blend pot to the pcb?

    since i am in the process of purchasing a nice jazz bass to become my main axe, i was planning on keeping the bb1500 as my backup (i always bring a backup to gigs). I have a actually thought, many times, about replacing the preamp in the yamaha - simply because i feel that the one in there at the moment really doesn't do it justice. But as it's moving down the line from top spot very soon, i can't really justify replacing the pre at this point in time.

    i had another gig last night and it sounded fine. i might just take it to my amp tech and see if he can do a quick fix on it.. that might be the best sollution!

    cheers!
    andy
     
  4. luknfur

    luknfur

    Jan 14, 2004
    DIXIE
    If you just hit each blend contact in the PCB with a soldergun (sort of resoldering) you might get resolution. PCB's are subject to all kinds of wierd stuff so it may have nothing to do with the blend pot. It's easy and wouldn't hurt to try. You might be able to just wiggle the pot a bit and observe the PCB and see some movement in the contact.
     
  5. great idea. cheers for the advice again.. i'll probably give this a crack tomorrow when i've got a bit more time. but i'm teaching all arvo today.. so if a student skips i might bring a soldering gun along and give it a crack!

    thanks for the help,
    andy.
     

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