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Thread: Onix ULW-10 Subwoofer repair help

  1. #11
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    Default Re: Onix ULW-10 Subwoofer repair help

    Quote Originally Posted by moris4wildlife View Post
    BTW, I've been in awe reading the reviews on the Sierra 2s. I've been thinking, even though I've been thoroughly pleased with the first edition CMB 170s for the past 10 years, wouldn't it be nice to crank up some hard rock and hear no distortion in the highs? I can't fathom this concept from a bookshelf speaker, no distortion in the highs?! (at least that's what I'm reading). I'm so anal about things like this, now I'm thinking about saving up for the 2s, despite them being out of my price range. But, then again, what's more satisfying than listening to the quality of sound that is exhilarating, euphoric. Congratulations.
    The tweeter in the CBM-170SE (as opposed to the ones that were in the "classic" CBM-170) would also be an improvement in that regard.

    That said...I think the Sierra-2's are VERY special.
    -curtis

  2. #12
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    Feb 2014
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    Monterey Bay, CA
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    Default Re: Onix ULW-10 Subwoofer repair help

    Quote Originally Posted by curtis View Post
    The tweeter in the CBM-170SE (as opposed to the ones that were in the "classic" CBM-170) would also be an improvement in that regard.

    That said...I think the Sierra-2's are VERY special.
    Hi Curtis - Thank you for the suggestion. It is more realistic and practical for me. If you think the upgrade will be noticeable, I will seriously consider it in the near future.

  3. #13
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    Default Re: Onix ULW-10 Subwoofer repair help

    Looks like the middle PCB is the amplifier section. Although it is hard to tell from this angle, the middle PCB looks like it has 2 output transistors. Typically, each of these will have 3 leads that will be soldered to the PCB. They will also be securely mounted to the aluminum backplate (which acts as the heatsink). There will either be a heat conductive pad between the backplate and the transistor, or heat conductive grease (thermal grease). I recommend replacing both of these output transistors with the exact same transistors (as labeled on them) or finding a generic. I suspect the problem occurred due to poor heat sinking of the output transistors, which cause these IC's to fail -- typically due to internal solder joints breaking down, which is why the sub might work for a short period of time but after it gets warm, problems occur as the heat causes things to expand and conductive connections break down.

    Depending on the transistors, they can be as inexpensive as $10 each (or less) and its worth trying to replace them.

    Good luck and hope this helps!
    .
    .
    .
    Good Sound To You!

    David Fabrikant
    www.ascendacoustics.com

  4. #14
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    Feb 2014
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    Default Re: Onix ULW-10 Subwoofer repair help

    Thank you David. Seems like I may have a solution. I will take your instructions to a qualified electronics repair person, then cross my fingers. I'll report back later.

    Oh. I just remembered another question regarding the amp. Will changing the output transistors remove the very audible hum I've always heard through the sub? All of my other components are very quiet.
    Last edited by moris4wildlife; 03-06-2014 at 07:47 PM. Reason: One more question

  5. #15
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    Default Re: Onix ULW-10 Subwoofer repair help

    Well, just prior to taking the amp to the electronics shop, I took the speaker cone to a speaker repair shop to assess the subwoofer, just in case Dave was correct about the possibility of the speaker being fried (as he mentioned in an earlier post). She hooked up the speaker to her testing equipment and gave it some juice in a variety of frequencies, while I was holding the speaker. My hand was jumping and shaking but the speaker sounded clean; not a trace of a loose component. In fact, she was quite impressed with the clean sound and depth at which the little 8-incher could produce; she ended by saying that "it's definitely a keeper, the problem is not the speaker". So, I later dropped off the amp at an electronics shop, but got a call a few days later from the tech who said he didn't want to try and figure it out; that it would cost more to try and repair the amp than purchasing a similar one. So, this is where I stand now. I am looking to purchase a Dayton 250 plate amp that will drop right in; no modifying the box and the screw holes will match. Seems like a few HSU owners have used this amp with good success, so it's likely what I'll do. Just wanted to put some closure to this thread. Thanks to all for your advice.

    September 4 Update- I purchased the Dayton SPA 250 from Parts Express and have used it for about 5 months. So far so good. The sub sounds tight, clean, musical and punchy. Now I hope it holds up. There seems to be a small percentage of amp failure with this model, based on reviews by other owners.
    Last edited by moris4wildlife; 09-04-2014 at 11:31 PM. Reason: Update

  6. #16
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    Default Re: Onix ULW-10 Subwoofer repair help

    Quote Originally Posted by curtis View Post
    The tweeter in the CBM-170SE (as opposed to the ones that were in the "classic" CBM-170) would also be an improvement in that regard.

    That said...I think the Sierra-2's are VERY special.
    Curtis - Just curious, but what difference do you hear in the sound of the 170 SE vs the original? I will audition the SE when I'm down in SoCal in two weeks. I'll also listen to the Sierra 2s, knowing its out of my budget, but I would like to hear how special they are.

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