Phono stopped working on SX-880

Discussion in 'Pioneer Audio' started by whosnotwo, Apr 7, 2017.

  1. whosnotwo

    whosnotwo New Member

    Messages:
    4
    Hello everyone. Forgive me if there is already an answer to this. I did a quick search and didn't see anything.

    I have had my Pioneer sx-880 for a few years and absolutely love it. I was listening to records yesterday when all of a sudden the music stopped. The turntable was still spinning and the 880 was still on. The tuner, tape, and aux input all work. But the phono input will not produce a sound. Somehow, the phono part is bad while everything else works.

    Any ideas on where I could start troubleshooting? Does this sound like an "easy" fix or is my unit completely shot?

    Any assistance would be greatly appreciated. Thanks!
     
  2. rcs16

    rcs16 Super Member

    Messages:
    2,958
    Location:
    Baldwin, Ontario, Canada
    Just because the TT is spinning does not mean it is putting out a good signal. test your TT, try the TT in another receiver or try another TT hooked up to the 880 for verification.
    If it is the 880 then and both phono channels do not work then it could be a supply issue to the phono IC, Q1,2, it is supposed to be ~ +/-24V. The +/-25V is common to both the phono(Q1,2) and pre-amp(Q3,4) sections. There is only a R/C filter separating them (220 ohm R and a 100uF/25V ecap).You will need a DMM in order to test these DC voltages. It should be fixable imo.
    I doubt that it is the selector switch if both phono channels are non-op.

    Good Luck
     
  3. whosnotwo

    whosnotwo New Member

    Messages:
    4
    Thanks so much! I'll give it a try.
     
  4. slimecity

    slimecity Super Member

    Messages:
    1,878
    Location:
    New Zealand
    Losing both channels at once from your TT is unusual. Are there any microswitches in your TT that cut the sound once the arm finishes playing and returns to the holder? That's the fist place I would look after testing to see if your TT is still outputting a signal, as above.
     
  5. whosnotwo

    whosnotwo New Member

    Messages:
    4
    I hooked up the TT to another receiver and it works fine. It's really strange that it just stopped playing mid song without any other issues. Both the TT and SX880 are in great shape.
     
  6. markthefixer

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

    Messages:
    20,658
    Location:
    Bensenville,Illinois
    waiting on those voltage readings, do you have a DMM? Know how to use it (we can instruct in that )?

    the left and right channel phono each have their own amplifier chip

    the only commonality is the power to both these chips, and that power comes from the pre-amp stage, and since your pre-amp stage is demonstrably working, it can only be one of two resistors, two capacitors or one of the two phono amp chips shorting out the power to the other channel's phono amp chip.
     
    slimecity likes this.
  7. whosnotwo

    whosnotwo New Member

    Messages:
    4
    Hi. I do have a voltage meter, but only know how to use it in one position. Any help would be appreciated. Thanks!
     
  8. markthefixer

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

    Messages:
    20,658
    Location:
    Bensenville,Illinois
    Please post the manufacturer and model of the meter, or a good clear picture of it.

    We will instruct you in the settings, where to connect the black DMM lead, how to prepare the red DMM probe for use and where to probe with it (on certain pins on the chips that are the phono amp)
     

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