Powerlite QSC power amp caught fire

Discussion in 'The Workbench' started by Australian, Oct 24, 2021.

  1. Australian

    Australian Green Beret VIP Member

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    IMG_8078.jpeg

    I turned on my power-amp which runs my RCF PA speakers the other day and I heard some crackling, and then smoke started to pour out of the vent at the front, and it was flicking in and out of Protect mode.
    I quickly turned it off. I then tested it again and one channel is working only, but it now stays in protect Mode(red LED on).

    I then tried it without the speaker cables plugged in and its still stays in protect mode. Any suggestions?

    btw, I've owned this for decades, so I'm wondering if its worth fixing or not?
     
    Last edited: Oct 24, 2021
  2. Pete Farrington

    Pete Farrington Well-Known Member

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    If you or a friend have got some seriously good skills fixing solid state stuff, then absolutely.
    Otherwise, a Behringer etc may be cheaper than a professional repair.
     
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  3. thetragichero

    thetragichero Well-Known Member

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    i feel like solid state stereo rackmount power amps can be had dirt cheap on the used market these days. i picked up a crown (200w/channel), graphic eq, crossover, and an skb rack case for $200 off craigslist. i only really needed the power amp (another rack case is also nice) so i sold the other two components for almost what i paid for everything
    also picked up a stereo 800w/channel power amp for my backup bass rack for 75 bucks shipped off reverb because it seemed it only needed a volume pot replaced
    in other words, unless you're using it in some mission critical application (in which case, buy something brand new with warranty) just cycle in used stuff
     
  4. Matthews Guitars

    Matthews Guitars Well-Known Member

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    I have a fair amount of experience with QSC amps. I run a pair of MX1500As in my home theater system. Every ten years they need their filter capacitors replaced or they will eventually experience serious damage when the caps leak and they short out and burn a big hole in the PC board. This requires a significant repair job on that channel.

    There should be a notification printed on every QSC amp: 10 year cap replacement is mandatory. Do not skip this service or the amp will die horribly. This is not a joke.

    I love my QSCs but that is something you have to know about them.

    My QSCs are also modified with added Speakon jacks as well as added "Audiophile" grade RCA input jacks.

    To me, QSCs are high quality amps that are worth recapping every ten years. Or even worth repairing if ONE channel is out. They are not cheap throwaway amps like you can find under other brand names.
     
  5. PelliX

    PelliX Well-Known Member

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    This ^ 100%. Good amps, but they need some cap love sometimes. I've worked with them professionally and really liked them. Give us some gutshots and and we might be able to say more about the matter.
     
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  6. Australian

    Australian Green Beret VIP Member

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    I’m going to post up some pics of the insides later.
    Hopefully I can have it serviced and let it live on to serve its master. :)
     
  7. Australian

    Australian Green Beret VIP Member

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  8. Australian

    Australian Green Beret VIP Member

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  9. Australian

    Australian Green Beret VIP Member

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  10. Australian

    Australian Green Beret VIP Member

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  11. Chris-in-LA

    Chris-in-LA Well-Known Member

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    That cap is toast. I hope it’s not too big a job to recap that thing.
     
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  12. PelliX

    PelliX Well-Known Member

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    Yup, that's a vented cap, alright. WIth a little luck it's just a replacement of that one to get it working again. I'd replace that whole set of electrolytics, though. If you don't, one of the others is going to give up on you. Should be quite straightforward if you have somebody who knows anything about soldering. :thumb:
     
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  13. Australian

    Australian Green Beret VIP Member

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    I’m going to take it to a tech tomorrow and get him to service it. Even if he chatges me a couple of hundred bucks its worth it.
     
  14. thetragichero

    thetragichero Well-Known Member

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    all of that carbon will need to be cleaned up, and if any of the board is charred those sections will need to be cut out (carbon is conductive and you could very well end up with voltage where it isn't supposed to be). will be anywhere from a not fun to a total pain in the ass job, so definitely worth paying someone else to do it!
     
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  15. Matthews Guitars

    Matthews Guitars Well-Known Member

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    Yes, you replace all the power supply reservoir capacitors as a set. Otherwise you're leaving time bombs in among the new ones, and they WILL blow up.

    See if equivalent but higher rated capacitors are available for it. Same voltage and capacitance rating, same case style and dimensions, but in higher hours/temperature ratings. Rather than the default 85 degrees C and 1000 hours rating, if there's better available, get them. Such as 105c 5000 hours. Or even 105c 10,000 hours. THOSE should be lifetime parts.

    I buy most of my capacitors (other than for guitar amps) from Digikey. And they have a BROAD selection to pick from.
     
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  16. Australian

    Australian Green Beret VIP Member

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    Bad news. :erk: My beloved workhorse has been put down.
    I took it to two techs and they both suggested that I just buy a new one. They both said it would be at least $300 to fix.

    So I'm just going to get a new Behringer .I was thinking this one, but read some reviews that the fan is noisy. Anyone here heard one of these?
    Behringer-KM1700-Power-Amplifier.jpg
     
  17. Australian

    Australian Green Beret VIP Member

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    Update. I found another very good tech who's had a lot of experience with these amps. So It may live another day. :woot:


    "Hi Lewis,
    We know these well , so should be able to sort this out for you.
    It does look fairly nasty, so I can't give you an estimate of cost without having a better look.
    You can drop it in any time, but call first & may take a while since we’ve just returned from 3 months enforced break.

    Cheers."
     

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