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Pioneer SX-1250 Keeps blowing speakers right channel, Ideas Help?

Discussion in 'Pioneer Audio' started by electrocuted, Oct 9, 2018.

  1. electrocuted

    electrocuted New Member

    Messages:
    37
    Location:
    South Florida
    Hi All,
    I have a recently bought sx1250, although it sounds very good it seems to keep blowing the speakers in the right side. Never run volume past 12-1 oclock and have fairly good speakers. So far it cooked an HPM 100 with the 200 crossover, a brand new set of Klipch Reference 820s rated for 150watt continuous and 600 watt peak. It also popped the fuse in a Cerwin Vega D-7 12".
    I am wondering who may have ideas where to start chasing down what type of problem.
    Thanks
     

     

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  2. petehall347

    petehall347 the brandy coffee man Subscriber

    Messages:
    28,084
    Location:
    uk.. the middle bit
    what does it blow in the speakers ?
     
  3. restorer-john

    restorer-john Addicted Member

    Messages:
    6,522
    Location:
    Australia
    Sounds like it could be turning into an oscillator...
     
  4. petehall347

    petehall347 the brandy coffee man Subscriber

    Messages:
    28,084
    Location:
    uk.. the middle bit
    my initial thoughts too . . never easy without history of the unit or at least some pics of inside to see if someone has been messing around in there .
     
  5. electrocuted

    electrocuted New Member

    Messages:
    37
    Location:
    South Florida
    I sent the HPM woofer and mid range out to be rebuilt and have not yet heard back from him yet. I think it is the coils because they showed open circuit. The woofer was a tad rough pushing in and out on the paper cone but not that bad.

    The Klipch lost the entire tweeter section on both I believe because they sounded very flat, they were brand new and I was able to exchange them due to the extra service plan I purchased but I cannot keep humping speakers back and expecting new ones.

    So far the Cerwins D 7s sounded good but the 1st time I used them the right speaker blew the 2.5 amp fuse.
    What gets me is overall the unit sounds great until.....the speakers stop dead.

    I have shut it down until I figure this out.
     
  6. electrocuted

    electrocuted New Member

    Messages:
    37
    Location:
    South Florida
    Can you further detail what you mean by turning it into an oscillator?
     

     

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  7. electrocuted

    electrocuted New Member

    Messages:
    37
    Location:
    South Florida
    I don't have history because it was an fleabay deal.

    I did grab a full recap set which I believe has about 96 or so caps and transistors including the 4 big ones. I am going to get set up to do that job soon. I am just trying to read and get enough info on how that project is done.
    This speaker thing has me worried though.
     
  8. petehall347

    petehall347 the brandy coffee man Subscriber

    Messages:
    28,084
    Location:
    uk.. the middle bit
    as i first thought . tweeter main problem but however seems more of a dc problem with burned coils woofer mid ranges . this should not happen .. picture time and dc voltage reading of speaker outputs .
     
  9. markthefixer

    markthefixer On Hiatus, dealing with Dad's estate full time Subscriber

    Messages:
    21,117
    Location:
    Bensenville,Illinois
    Check for DC offset at the speaker terminals.and a borked (or bypassed) protection circuit. (fleabay grrrrr...)

    PLUS I had an amp in that was putting out lots of second harmonic distortion in one channel and it sounded fine to me.

    THIRD harmonic etc comes from clipping and is quite noticeable.
     
    merlynski likes this.
  10. petehall347

    petehall347 the brandy coffee man Subscriber

    Messages:
    28,084
    Location:
    uk.. the middle bit
    just where i was going . hence asking for pics .
     
  11. electrocuted

    electrocuted New Member

    Messages:
    37
    Location:
    South Florida
    I will get some pics asap, I need to clear some bench space and open the monster up. This is my 1st big one in over 40 yrs since we built the radio kits in school.
    I can solder anything big small/ silver/ brass/ stainless ect.
    Funny, I bought the amp to listen to music while doing other projects....
     
    merlynski likes this.

     

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  12. electrocuted

    electrocuted New Member

    Messages:
    37
    Location:
    South Florida
    I know fleabay ..... I always wanted this one since they came out in high school, I still like things loud with a lot of horsepower.
    I was going to pick up a meter with an ocsilliscope feature, do you or anyone have a fairly moderate recommendation? I do not use a scope that much in my A/C trade and would just want one able to do this job?
     
  13. Harvestor

    Harvestor Super Member

    Are you playing a CD or Turntable Album or MP3 or what???

    The absolute highest I run my Receiver volume is 3.8 not even 4 on FM Radio...& When I play the Blu-ray player I use as CD player I go no higher than 3.2 .... Because the receiver is at full RMS power and Well UNDER Clipping threshold .... Your Speakers must be very very inefficient. .
    My "Guess" is you are overdriving the speakers and Clipping the Amp in the Receiver. ....
     
    Dave1384 likes this.
  14. electrocuted

    electrocuted New Member

    Messages:
    37
    Location:
    South Florida
    I have been doing both MP3 and the CD player as of last week because the Music was much cleaner sounding, but I only have a limited amount of CDs vs hundreds of options for tunes on mt MP3
     
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  15. Harvestor

    Harvestor Super Member

    I should have said also...

    I know you are Not Running inefficient speakers so that Can't be the problem with why you are needing to dial up 1 O'clock on the volume knob
     
    Dave1384 likes this.
  16. Harvestor

    Harvestor Super Member

    Somebody here is going to be able to get you much closer to diagnose more accurately than I... ...
    But my guess is that the Receiver needs a complete Re-Cap and Bias alignment etc on of the output transistors might be sending too much voltage ....
    It's worth every penny to update and make it Right...
    It will outlive us both afterwards
     
    Dave1384 likes this.

     

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  17. electrocuted

    electrocuted New Member

    Messages:
    37
    Location:
    South Florida
    Well to be honest I do like it loud for starters, 2nd I use this system in my barn area with a large area. I do not like any type of noticed distortion so I never push things that hard.
    I have a Carver hr 895 with 125watts (I believe the Carver is 125 or could be 110 per- Ill check that tonight) per ch and never had any issues with popping speakers, and like I said it only seems to be acting up on that one channel/side.
     
  18. electrocuted

    electrocuted New Member

    Messages:
    37
    Location:
    South Florida
    I'm thinking (hoping- knock wood) that you hit nail on head. I will get ready to do that job after I collect enough info on how to do it.
     
  19. Harvestor

    Harvestor Super Member

    IMG_20180212_011831174~2.jpg
    Believe me I like it LOUD also..and I have a set of D9'S and Mach ones and Acoustiflex model 12's
    And then my Ohm's
    IMG_20180914_134135241.jpg
     
  20. electrocuted

    electrocuted New Member

    Messages:
    37
    Location:
    South Florida
    SICK!!! See I have been searching the local area for the D9's and you just made me real jealous, now I gotta have them. You probably rattle the guys dishes 4 doors down the street.
     
    Harvestor likes this.

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