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Clearcom popping...

Discussion in 'Sound, Music, and Intercom' started by Anonymous067, May 31, 2009.

  1. Anonymous067

    Anonymous067 BANNED USER

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    When we fire up our clearcom system (a phase of the sound system power-up), occasionally, the clearcoms give us a nasty pop...pop...pop...pop...in all the earmuffs. The two ways I can make it stop is...
    a) unplug half the headsets until it kinda fades off.
    b) hold the remote mic kill button for a few seconds.

    The odd part is it only happens like...two weeks into using headsets...

    what could be causing this?
     
  2. DaveySimps

    DaveySimps CBMod CB Mods Premium Member

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    If it is only a single pop or two just upon power up, I would not worry about. All ClearCom systems I have used do this upon powering the system on. It is sort of akin to the sound you get when powering down a sound board while the speakers / amps are still on. If it happens at any other time, I would say you have some issues, like a short in a wire or something of that nature. That is my $0.02

    ~Dave
     
  3. Van

    Van CBMod CB Mods Premium Member

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    Sort of sounds like a bad dolder on a cable somewhere. Occasionally a bad solder or bad connection can create a "capacitance" issue - that is- they build up a lottle charge then let it go, resulting in the square wave pop. The hard part is isolating it, whether it's in the cable, on one of the belt packs mother boards or in the head unit.
     
  4. 00AVD

    00AVD Active Member

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    Might be worth checking the power supply / master station. It sounds a little like the "motor boating" that can occur when a power supply can't deliver enough instantaneous current at power-up.
     
  5. waynehoskins

    waynehoskins Active Member

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    That would jive with it being related to the number of intercom stations on the bus. But since these things draw next to nothing, and the power supplies are usually sized for more stations than you usually need anyway, I'd look more at a cable (could be loose connectors too) or a faulty beltpack.
     
  6. 00AVD

    00AVD Active Member

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    I was more thinking of a faulty PSU, not an undersized one. When the main filter capacitors go low capacitance, "motor boating" or other instability is a common symptom in audio equipment.
     
  7. Anonymous067

    Anonymous067 BANNED USER

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    It will continue until somebody either unplugs a couple headsets (usually the easy to reach ones in the booth), or I found that pushes then "kill switch" stops it immediately.

    I don't think it's to blame on loose connectors on the outside of the system, and I also checked everything on the backs of the racks (the ones I have access to). Same problem.

    Just to clarify, its not just a few pops at system startup, its continued for minutes if nobody does anything.
     
  8. Chris15

    Chris15 CBMod CB Mods Premium Member

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    Then something is oscillating that shouldn't be.

    Have we confirmed the party line is terminated?
     
  9. Anonymous067

    Anonymous067 BANNED USER

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    Our base station has 6 party line connectors on it, all hooked up to wall jacks (some are daisy chained, no doubt, because we have 20 jacks around the facility).

    The backs of the wireless clearcom units have a "pl in" and a "thru". the thru is not used, but isn't this self-termed?

    Any other questions?
     
  10. 00AVD

    00AVD Active Member

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    I've never seen a separate terminator for ClearCom style systems. As far as I'm aware, they are only terminated in the PSU / base station.
     
  11. waynehoskins

    waynehoskins Active Member

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    Yep. Although "termination" is a bit midleading -- it's not matching a line or load impedance like we would do with radio or digital transmission lines; instead, it's a bus loading. Its purpose is to hold the bus impedance significantly lower than any reasonable number of stations would pull it, so that changing the number of stations on the bus makes no significant (or usually, even detectable) change to the bus loading, and consequently level.

    The bit about the RMK button fixing things makes it sure sound like a station, rather than power supply, problem.
     

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