Ampeg B410 HLF PCB melting fault?

Discussion in 'Amps and Cabs [BG]' started by Jason Keller, Sep 30, 2016.

  1. Jason Keller

    Jason Keller

    Sep 22, 2016
    Hi all,
    This is my first post so hello and thanks for taking the time to read!

    Ok, a few weeks ago (on day one of a European tour, no less) my bass amp failed again at sound check. I immediately pointed my finger at the head and started yelling profanities and threats at it. Turns out it was the cab. I tested all the speakers and they work fine and have the correct Ohmage readings on my multimeter (although the horn has never worked for some reason, even though it reads correctly on the multi meter, but that reason may transpire shortly)

    I opened up the plate where the inputs and horn switch are, and lo and behold- melted terminal.

    Clearly this is the reason why it wasn't working, but what would cause this to fail so unspectacularly?

    Any ideas guys?

    It's a pretty easy fix if all I have to replace is the terminal and do a bit more soldering, but if the cause is deeper routed I'd like to know what it is so I don't end up with more meltiness on my hands.

    You'll notice that the blue wire and white wire have gotten so damn hot they've melted the terminal and the terminal legs which connect directly to the blue and white have actually melted off the solder and lifted from the board...

    Any help greatly appreciated!

    Best, Jason

  2. RoadRanger

    RoadRanger Supporting Member

    Feb 18, 2004
    NE CT
    Do yourself a favor and toss the connectors and solder the wires right in. I've seen way too many of that type connector burn up for no reason.
    Jason Keller likes this.
  3. Jason Keller

    Jason Keller

    Sep 22, 2016
    Really? Ok that makes me feel better if it was a faulty connector.
    One less component to think about I guess..
  4. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa Boogie, Development Engineer-Genzler (pedals), Product Support-Genz Benz
    This can be a problem where the insulation displacement connection on the female (wire) side does not make good contact when the connector is assembled.

    IMO, directly soldering is the only practical repair, unless you just replace the wire harness and the male connector.
    Jason Keller likes this.
  5. Jason Keller

    Jason Keller

    Sep 22, 2016
    Thanks! That's two for direct soldering then so far. I guess my main concern was that it could be a faulty resistor and that simply soldering the wires wouldn't get to the root of the problem, but directly soldering it seems to be the way to go.
  6. BassmanPaul

    BassmanPaul Inactive

    Make that three for wiring direct. :D
    Jason Keller likes this.
  7. Jason Keller

    Jason Keller

    Sep 22, 2016
    Ok I'm starting to see a pattern. Haha
    BassmanPaul likes this.
  8. BogeyBass

    BogeyBass Inactive

    Sep 14, 2010
    or if you don't need the tweeter
    wire the cabinet as a full range cab and bypass the board all together
    Jason Keller likes this.
  9. BadExample


    Jan 21, 2016
    Welcome Jason!

    I don't know why they use those connectors if they can't get them snapped down properly. They are reliable with the proper tooling and training.
    Jason Keller likes this.
  10. john m

    john m Supporting Member

    Jan 15, 2006
    There's always a reason.

    A loose/poor connection has a higher resistance then the rest of the components in series. Current starts to get limited as the resistance goes up but----- heat at the poor connection causes the destruction and ultimate failure of the system.

    Heat ie watts = I squared x R ; many house fires have been caused this way,
    Especially ones wired with aluminum wire connected to copper screw terminals---
    Thermal creepage takes place.

    Eliminating the terminal and soldering the wire directly to the circuit board is a great remedy formth OP.
  11. Jason Keller

    Jason Keller

    Sep 22, 2016
    was tempted to do that, but I just ordered a Novation Bass Station 2 so i'm thinking that tweeter may come in handy after all..
  12. Jason Keller

    Jason Keller

    Sep 22, 2016
    thank you!

    yeah it's a mystery to me. everything else about those cabs is SOLID. Bizarre..
  13. Jason Keller

    Jason Keller

    Sep 22, 2016
    I'm also thinking this is why I constantly had to take my Hi Watt Custom 100 for repair, and why my Orange OB1-300 had been acting so weirdly.
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