BFR Feb 2020
Results 1 to 7 of 7

Thread: Preamp board in music man bass

  1. #1

    User Info Menu

    Preamp board in music man bass

    We were at my studio jammin and the battery went dead in my bass. I accidentally installed it backwards in the flip out style battery compartment. I reinstalled the battery correct but have no sound now. I tested the pc board to see if I am getting voltage on the board and I'm getting about 8.6 volts. I have the boomerang style pc board with the three band eq. I know if you wire up an effects pedal backwards you can fry it. Is this pretty much the case with a battery too? And if anyone know usually what goes bad in the signal path when this happens would also be helpful. Thanks

  2. #2

    User Info Menu

    It's more likely that you bent the contacts in the battery box.
    slightly out of date pic

    l to r:

    Franken-Bongo 5 HHp (The Billy Bass), refinished fretted cigar leaf satin finish neck, daphne blue, mint pickguard, EB Cobalts.

    Dargie Delight Bongo 5 SHp, fretted, Dargie, b/w/b pickgaurd, Dargie. Ernie Ball straplocks. Flats.

    Franken-Bongo 5 SHp (Moby, the White Whale), refinished vintage gloss unlined fretless neck, white, tort pickguard, EB Cobalts.

  3. #3

    User Info Menu

    I tested and have 8.6 volts on board.

  4. #4

    User Info Menu

    Bassmonkee is talking about the little metal pieces inside the battery box that make contact when the battery is inserted. They can get bent down which prevents the battery from making full contact. All you need to do is remove the battery, and gently reach underneath the the two metal pieces with a small screwdriver and pull them up slightly. It's the easiest and cheapest fix, so hopefully its nothing more complicated than that.

  5. #5

    User Info Menu

    I would fire off an email to customer service. I don't know if the preamp has protection for reverse wiring. If you are getting voltage to the board, I would assume both contacts are connected.
    2007 Stingray 5 HS Cherry Burst / Maple FB / 3 Band EQ / Ceramic Pickups
    2012 Stingray 5 H Pearl Blue / Rosewood FB / 3 Band EQ/ AlNiCo Pickup
    2012 Steve Morse Morse Blueburst / Rosewood FB
    2012 Luke III SSH Vintage Sunburst / Rosewood Neck

  6. #6

    User Info Menu

    Ok, I finally figured it out

    First of all thank you for all who have responded. By installing the battery backwards I fried my 8 pin op amp. Talked to the folks at music man. On my board there is no internal protection. I purchased a new TL072 in lieu of the previous TL062 op amp, because this is the new one that replaces it for 2$ at my local electronics shop. I also installed a plug in style base for it in case I make the same mistake again. Anyhow, I hope this will be helpful if anyone runs into this problem. Just remember if you do this, the op amp has to have the same positioning (polarity), when doing this. All you need is some soldering skills.
    Also, from an engineering standpoint it would be cool if the engineers had a enough forethought to make it impossible to put the battery in backwards by making one hole smaller to except the battery only one way. But, sometimes imperfection may be what makes something unique-lol


    Last edited by stlmusicman; 05-25-2013 at 09:26 PM.

  7. #7

    User Info Menu

    Bump! I’m thinking this may have happened to my newish sr5, it lacks power punch and clarity.. how can I Check the opamp is faulty? Tia

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
Ernie Ball Forums