Subwoofer Repair SKW-HT240

Discussion in 'General Electronics Chat' started by Reeves360, Apr 6, 2010.

  1. Reeves360

    Thread Starter New Member

    Apr 6, 2010
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    My Onkyo sub died on me and I was hoping for some helpful tips to diagnose the problem.

    Here's what happened, my sub was working great BOOM BOOM while I play Battlefield Bad Company 2. Then all the sudden no more bass. Maybe the speaker popped during a loud explosion but I didn't notice.

    The sub currently can detect when there is a signal going to it from my amp and switches between red and green lights like it should. There is no sound coming from the amp at all. The speaker doesn't pop or click when you touch the input.

    So I took the back plate off and tried to check around. Nothing on either of the boards I found inside look burnt. The circuits and caps look fine when I gave them a quick inspection. I checked 2 or 3 fuses that I could find for resistance and didn't see any issues.

    I also checked the - and + of the RCA input on the back of the sub by finding the 4 pin connector on the little circuit board that's attached to the RCA port and back plate (sorry I don't know what this piece is called, please enlighten me). Everything appeared to be fine on this piece as well.

    I do not smell anything thing remotely close to a burnt smell coming from the sub.

    Any help on what I should be looking for or what I can test next would be great.

    Sorry if I have missed any posts on how to do this, I used the search function but didn't turn up any promising leads. I'll keep searching while I wait for an answer here.

    Thank you all in advance!
     
  2. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    Boom Boom went BAAAANG! :D

    So let's get banging.
    Do you know how to solder, test resistance and measure AC DC Voltage?
     
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  3. beenthere

    Retired Moderator

    Apr 20, 2004
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    My oldest kid had the same thing happen - the voice coil opened up.
     
  4. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    GASP !!!:eek: The Kid or the Speaker?
     
  5. retched

    AAC Fanatic!

    Dec 5, 2009
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    The kid, dummy. You should see the line at the doctors office for kids with their voice coils hanging out of their necks.....eww..


    @Reeves360
    Ok. The next step for you would be to disconnect the SPEAKER itself from the amp board. You can try a continuity test on the speaker connectors. If you have none, time for a new speaker.

    You can also take the speaker out and try it with a similarly rated output source. Maybe a book box or a home audio system. Hook the speaker up to the speaker out on another amp and see if the speaker still works.. Im guessing no.

    You may have bought one of those 600WA systems that are 6 watts. The hair thin voice coils are good for about...well nothing really.
     
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  6. awright

    Well-Known Member

    Jul 5, 2006
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    If you have an ohmeter measure the resistance across the voice coil. Should be down around a few ohms.

    You can also perform a quick continuity check with an AAA, AA, C, OR D cell across the voice coil. You should hear a click or a scratching sound as you make contact with the battery. You cannot damage the voice coil with a 1.5 volt cell.
     
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  7. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    lmaof......... :d
     
  8. Reeves360

    Thread Starter New Member

    Apr 6, 2010
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    I do know how to solder but not very well and I'm willing to try. I also have some friends that are pretty good with a solder gun but aren't speaker experts they're car guys. :)

    I'm also very willing to try my best and am not afraid to break anything seeing as I have nothing to loose. :D

    I just went out and bought a new multimeter last weekend because it wasn't testing Ω resistance at all but volts and amp worked fine :eek:

    So I think I'm good to go if you guys tell me what the best place to start testing and looking for problems.

    I can also take pictures of the stuff in side the sub box if that helps out at all.

    Thank you all so much for getting back to me.
     
  9. Reeves360

    Thread Starter New Member

    Apr 6, 2010
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    Thanks for the help retched and awright!

    I’ll test the speaker directly with the speaker connectors. I should be able to do that tonight or tomorrow at the latest, seeing as I work 4 x 10’s M – Thurs I should have time this weekend.

    I will also try to take some various pictures of the sub and post those up just incase it might help.

    For some additional information I have a Onkyo TX-SR805 amp powering Onkyo SKS-HT240 speakers.

    Feel free to click on those links for the model I have to go to the manufactures web site for additional information and specs.

    Once again thank you all for the help!
     
  10. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    OK. Post picture of the board
     
  11. Reeves360

    Thread Starter New Member

    Apr 6, 2010
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    Speaker Resistance 4.5 Ohm which I'm assuming is within spec for a 4 Ohm speaker?

    I tested some 5.25” Rockford Fosgate car speakers and received a reading of 3.5 Ohm. These car speakers are also 4 Ohm speakers.

    What should I test next and what does this new information tell us?

    Thank you all for the help.

    I haven’t got around to taking pictures yet but I will soon.
     
  12. Audioguru

    New Member

    Dec 20, 2007
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    A 4 ohm speaker is 3 ohms DC and shows 3.5 ohms on a multimeter because the leads are about half an ohm.
    My car has some 2 ohm speakers.
     
  13. flat5

    Active Member

    Nov 13, 2008
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    Before throwing out your old meter see if it needs a fresh battery.
     
  14. Reeves360

    Thread Starter New Member

    Apr 6, 2010
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    I'll check the batteries on the old multimeter before I throw it out, thanks for the tip.

    Any other suggestions on what I can test to see if I can get this thing working?
     
  15. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    can you show us the board.
    I need to see it to tell u what to do.
     
  16. Reeves360

    Thread Starter New Member

    Apr 6, 2010
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    I finally found the cable for my digital camera!

    Let me know if you need more.

    Thanks for the help!
     
  17. Reeves360

    Thread Starter New Member

    Apr 6, 2010
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    Here is a couple more.
     
  18. Markd77

    Senior Member

    Sep 7, 2009
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    I'm not sure I've ever seen a board with the components marked front and rear. That is an awsome idea, hope it catches on.

    Check the fuse on your old multimeter too. You might have to open it up. They blow quite easily.
     
  19. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    What is ? :confused:

    Let me check the board and I'll reply later
     
  20. SgtWookie

    Expert

    Jul 17, 2007
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    They mark them if they are mounted on both sides of the board.
    It's not a new idea.

    Fuses in multimeters open up quite easily if you try to measure current without knowing what current you are measuring.
     
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