Bang Bang and my systems dead! Help!

Discussion in 'AV Receivers' started by Rajj Nair, Oct 10, 2007.

  1. Rajj Nair

    Rajj Nair Stunt Coordinator

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    hi,
    i needed some advice:
    i recently went separates and am using my Denon 1905 receiver as my processor feeding into an Emotiva LPA1 feeding into PSB 5T and 9C and PSB surrounds.

    i rewired the setup to the new system, and absolutely loved the sound.

    but everytime i play a movie at decent levels (-20 to -15), after about 15 to 20 minutes or so, theres a series of loud "bangs" or "pops" and then my receiver shuts down.
    the LPA-1 amp is all lit up and ok but the denon just shuts down.

    upon shutting the entire systems down, the denon cycles through its setup and then shuts down again,

    any advice anyone?
    thanks,
    RN
     
  2. Brent_S

    Brent_S Second Unit

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    Since this happened after you rewired everything, you need to start by checking all of you wiring/cabling for shorts. Generally, if an amp's lights are "all lit up", it indicates that a fault condition has been triggered...are you sure LPA-1 is ok? I see two rows of LED's in the photos, one of which looks like normal/power on so the second row being lit would probably indicate a fault condition like shorted speaker leads or overheating.

    The 1905's manual indicates that the display will react certain ways, such as a flashing power button, to signal a trouble condition. Might be worth reading.
     
  3. Rajj Nair

    Rajj Nair Stunt Coordinator

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    thanks brent,
    the lpa is doing fine, the lights that are lit up are the blue lights, they turn red if one of the wires had shorted, hence that seems fine.
    so its possibly the denon, im thinking.
    would you know if the manual is available online? i did check and got one that didnt have any on flashing lights.
    i will check on the wiring asap and revert.
    appreciated.
     
  4. Rajj Nair

    Rajj Nair Stunt Coordinator

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    Thanks for your inputs, really appreciate them.
    I just re checked the wires, ensured no speaker cables going out of the receiver, no strands etc.
    Post playing a movie (Stealth in DTS) for about 15 minutes, the same 2 loud "thump" came through and the receiver shut down, and upon starting, before completing its usual cycle of checks, it just shut down midway and blinks a red circle around the on off switch.
    Both the denon and the LPA1 were cool to the touch.
    The loud "thump" or "bang" I mentioned comes from all the speakers at the same time, upon disconnecting the LPA1 amp, the thumps didnt come through the speakers, while the receiver did its cycle and shut down.

    Is this something within the Denon then? Do you have any further suggestions or ideas?
    Thanks,
     
  5. Girish

    Girish Stunt Coordinator

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    It may happen when either the circuit is getting overloaded at high volumes or the amp is not enough to drive the speakers at that volume.
    Try connecting the amp to a different outlet.
     
  6. Bob_L

    Bob_L Supporting Actor

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    Are these extraneous noises REALLY loud? So loud that they could blow one of your speaker drivers? If so, I think I'd stop experimenting and get the receiver into the shop.
     
  7. Rajj Nair

    Rajj Nair Stunt Coordinator

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    Girish, I will connect it to a different source and try.
    Bob, the sounds are really loud, I was a bit worried it might blow my speakers.

    I called Denon, the tech says theres apparently some feedback signal coming into the receiver and hence the receiver doing its bit to protect itself shuts down.

    The ring around the knob blinks red continuously, and I have to unplug the receiver before it come back again and then its ready, upon playing for another 10 minutes or so, it does the same thump, shut down, thing again.

    Denon tech has asked me to re-do the setup once more and if the condition persists to bring it into Denon for repairs.

    Heres a question:
    Do you think its faulty cables out of the receiver into the amp that could be doing?

    Im also going to try running the receiver on its own again and see if it behaves this way when not connected to the amp at all.

    This is frustrating, cause I just loved the sound when the system was playing well, but get to enjoy it just 10-15 minutes at a time
     
  8. Brent_S

    Brent_S Second Unit

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    The 1905's manual is available on the Denon website under "old products".

    There's nothing in the manual about flashing red light around the volume control so it may be a higher level diagnostic indicator. I think your next course of action, taking the LPA1 out of the chain and running on the receiver only is a good step. I would do a hard reset as shown on page 61 of the manual as well.

    It's possible, as the Denon rep suggested, the LPA1 has some sort of "bad" internal wiring that is sending current back throught the interconnect to the receiver...the receiver wouldn't like that very much. Static charges cause chips to behave in unexpected ways and it could be taking that 10-15 minutes of listening you're getting for the charge to build up to a point that it effects something.

    Any chance you had something powered up when you were swapping cables? That could potentially damage something in the Denon's processing circuits.

    What about normal CD playback, tuner listenting, etc...basically non-surround modes...what's the behaviour there.

    Good luck.

    -Brent
     

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