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Pioneer SX-980 Channel drop....distort...low volume

Discussion in 'Pioneer Audio' started by Mark Davis, Nov 7, 2018.

  1. Mark Davis

    Mark Davis Active Member

    Messages:
    121
    Location:
    Richmond, Virginia
    I have a Pioneer receiver that I recently got in pretty Mint condition.

    I recently set it up and started listening. I noticed occasionally it will play fine on FM and then the left channel will drop out.

    I tried plugging in my IPOD with a nice gold plated Aux cable. Same thing was happening.

    Yesterday I had the IPOD plug in everything was working fine.

    I went to plug in the power adapter for the IPOD and when I did the channel dropped immediately.

    Would you think this would be a grounding issue?????

    The stereos from the 70's only had a 2 prong plug on them.

    I still have other troubleshooting to do but thought I would ask in advance.

    Any input appreciated.

    Thanks in Advance!
     

     

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  2. Punker X

    Punker X Moderator Moderator Subscriber

    Messages:
    3,986
    Location:
    Panic in Detroit
    Moving this to the Pioneer forum since it has nothing to do with the FM section. Also with the recommendation you look up some threads on cleaning all the controls in receiver.
     
  3. dcgibby

    dcgibby New Member

    Messages:
    49
  4. merlynski

    merlynski Curmudgeon Electronicist Subscriber

    Messages:
    459
    Location:
    High Plains, Eastern Colorado
  5. Mark Davis

    Mark Davis Active Member

    Messages:
    121
    Location:
    Richmond, Virginia
    Does the Protection relay affect both channels or just one.

    I am having one channel drop and very low distortion out of the channel that dropped.
     
  6. Watthour

    Watthour Electron Rancher - JS3600

    The contacts in the relay can affect a single channel.

    Repair can be as easy are removing the relay cover and running a burnishing board between the contacts. However, while that may sound easy, accessing the relay and removing the cover can be a challenge. It is accessible from the bottom side of the unit.

    (Photo courtesy sawdust)
    [​IMG]
     
    merlynski likes this.

     

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  7. zebulon1

    zebulon1 Getting behind on work. I need help? Subscriber

    Messages:
    4,848
    Location:
    Las Vegas Nevada
    How about checking pin 8 on the protection board for ACv's when the receiver is operating with music?
    Wet finger the input to the left amp board pin 6? See if you hear a hum from the left speaker. Or touch the left jumper with your finger and check for hum.
    Don't forget to look at the jumpers for corrosion.
     
    Last edited: Nov 14, 2018 at 7:06 PM
  8. Mark Davis

    Mark Davis Active Member

    Messages:
    121
    Location:
    Richmond, Virginia
    Does anyone have directions on how to replace theis protection relay?

    Is it soldered on the bottom?

    I see the part number is 653-MY2-02-DC48.

    Mine looks totally different I guess it could be original.

    Do I just release the plastic clips holding the board on to get to the back side?

    Any other troubleshooting tips to determine if it is the relay?

    20181114_164546.jpg
     
  9. merlynski

    merlynski Curmudgeon Electronicist Subscriber

    Messages:
    459
    Location:
    High Plains, Eastern Colorado
    Is it soldered on the bottom? YES

    I see the part number is 653-MY2-02-DC48. YES

    Mine looks totally different I guess it could be original. I think so too.

    Do I just release the plastic clips holding the board on to get to the back side? YES

    Any other troubleshooting tips to determine if it is the relay?

    Once you get the board loose from the chassis you can try bypassing it, but that puts your output transistors and speakers at risk. If I am already in that deep I would just replace it. They are a 'usual suspect' for this kind of problem, along with all the other switch contacts in the signal path. I would try Deoxit on the front panel switches and pots, and exercise them repeatedly before replacing the relay, though. They are 'usual suspects' as well. If you can get the cover off the relay you can burnish the contacts and/or Deoxit them as well. As Watthour says in post 6 that can be a challenge.
     

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