MicroPro 3000: constant, loud rumble when turned on

My sub woke me up in the wee hours of the morning today. I thought a gigantic truck was rumbling through the neighborhood, but no, it was my sub. It was very powerful, throwing the driver to the extent of its range. I unplugged the LFE cable from the back but the sound continued. Only flipping the power switch stopped the noise. I unplugged for a while and tried turning on again, the noise was still there. I played with volume, crossover knob, and the little 12v/auto-sense switch, and nothing stopped this horrendous rumble. Well, switching to 12v stopped the noise mostly, only because I don't have a 12v trigger cable running to it, but having the switch to 'On' or 'Sense' allowed this terrible noise. When on 12v I could hear a faint hiss or hum still coming from the sub's electronics but I seem to recall this even when the sub worked normally.

As I mentioned, this happened in the middle of the night. The sub was set to 'Sense' but the receiver was off and nothing was playing.

Is my amp toast? Driver toast? Any way to reset the amp or otherwise troubleshoot this problem?

Much thanks for any advise!

Comments

  • Hello,
    In all likelihood there is a problem with the bass amplifier, best to call Polk at 1-800-377-7655 select option 1. Have the serial number and date of purchase available when calling.
    Regards, Ken
  • Hi Ken,

    Thank you for your reply What will they be able to do for me? I'm quite sure I'm past the warranty period so I don't imagine they'll be sending me a new one.

    Thanks!
  • ken brydson
    ken brydson Posts: 8,638
    mrceolla wrote: »
    Hi Ken,

    Thank you for your reply What will they be able to do for me? I'm quite sure I'm past the warranty period so I don't imagine they'll be sending me a new one.

    Thanks!

    How old is it? Amps have a 5 year warranty IIRC.
  • Hello,
    Actually the bass amp has a 3 year warranty and the woofer has a 5 year coverage. If you are outside the warranty period Polk can either repair the amp or offer a replacement. Since you've joined CP they offer a reduced price and shipping savings to members, so let them know. In any case begin with a call to them.
  • Yikes! Polk guy on phone said $600 for a replacement amplifier. I can get a brand new one on Amazon for $900. Yes, I'm out of warranty coverage. I forgot to ask about the CP discount. What does CP stand for? How much is the discount usually? If it's not 50% I'm not sure I'm interested. :-(
  • "Club Polk", I believe the savings is 20% reduction and free shipping within U.S.
  • rooftop59
    rooftop59 Posts: 7,952
    Yea, I’m a polk fan but to be honest I would take my $600 and buy an SVS SB1000 or 2000. (couple places have the 2000 for $699 shipped).
    Living Room 2.2: Usher BE-718 "tiny dancers"; Dual DIY Dayton audio RSS210HF-4 Subs with Dayton SPA-250 amps; Arcam SA30; Musical Fidelity A308; Sony UBP-x1000es; Squeezebox Touch with Bolder Power Supply
    Game Room 5.1.4:
    Denon AVR-X4200w; Sony UBP-x700; Definitive Technology Power Monitor 900 mains, CLR-3000 center, StudioMonitor 350 surrounds, ProMonitor 800 atmos x4; Sub - Monoprice Monolith 15in THX Ultra

    Bedroom 2.1
    Cambridge Azur 551r; Polk RT25i; ACI Titan Subwoofer