QB Midrange issue

Discussion in 'Infinity Loudspeakers' started by ASH556, Apr 30, 2018.

  1. ASH556

    ASH556 New Member

    Messages:
    12
    I picked up a pair of QB's off craigslist last week. The midrange speaker on one of them is not working. A local guy suggested pulling the speaker, running wires from an amp strait to it and seeing if it works as a trouble-shooting measure. Is that the place to start, or should I look at the crossover or something else first?
     

     

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  2. swechsler

    swechsler Frog Whisperer

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    4,887
    Location:
    7th row center
    That's one way to do it, but since the other one is working, try swapping the midranges between cabinets and see what happens. That should give you a pretty good clear indidcation.
     
  3. goodolpg

    goodolpg Just an old fart trying to help. Subscriber

    That would work but keep the bass/treble/loudness to a moderate level.
    Or do as swechsler suggested and just try it in the other cabinet.
    You could also disconnect the mid and check resistance across the driver leads.
     
  4. chef free

    chef free AK Subscriber Subscriber

    Messages:
    2,228
    Location:
    Hayward, Ca
    After testing the driver for continuity, check the pot, it may be dirty or the silver 12.5 uF cap could be bad. Those drivers are common but the ones with the built in box (Infinity part # 902-1179 is AD 5060/SQ8) are different than the ones without (Infinity part # 902-0151 is AD 5060/W8).
     
  5. Spitfirejoe

    Spitfirejoe Cheap Audio Aficionado Subscriber

    Messages:
    785
    Location:
    Fremont, Nebraska
    It's gonna be the pot, I betcha. Mine were scratchy but working when I refurbed the speakers, but MAN were they grungy. Followed someone's thread on here (Elnaldo?) that showed disassembling them and cleaning. Nice and clean now.
     
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  6. chef free

    chef free AK Subscriber Subscriber

    Messages:
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    Location:
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    I had one with a broken tinsel lead so there's one possibility...
     

     

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  7. elnaldo

    elnaldo Addicted Member

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    It wasn't me cleaning the pots. Never opened mine even if I restored the crossover. ;) (BTW I think I'm having problem with the Emit fuse holder, some dirty or oxide..)
     
  8. goodolpg

    goodolpg Just an old fart trying to help. Subscriber

    I've had the fuse holder act up before.
    Have you tried I different fuse?
    Fuses can look good but still be blown.
     

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