Pioneer SX 727 rotary selector fix/replace

Discussion in 'Pioneer Audio' started by cicada, May 14, 2018.

  1. cicada

    cicada Member

    Messages:
    81
    Location:
    New Zealand
    Hey Wise AK,

    I have purchased a replacement part for a broken SELCTOR knob (shaft/spindle arm, don't know how to call that) on a SX727, took a hit and cracked just at the base of the front facia.
    Part comes with wiring so color codes is not a issue, but still is a very tricky mission replace it,
    lot of soldering since is the core of all signals.

    I was wondering, can I approach this replacing just the center spindle/shaft thing (please suggest a name) so to avoid a day of headache?
    I have noticed there is a tiny bolt on the back, does it come out if I undo that bolt?

    Has anyone tried to do that folks?
     

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  2. Watthour

    Watthour Electron Rancher - JS3600

    If only the external shaft is broken on the original switch, the switch decks CAN be removed from the broken assembly and installed on the replacement shaft/detent assembly.

    BE AWARE that the tie rods which hold everything together also hold the spacers and washers between each switch deck. It will be critical to get every spacer/collar/washer back in its proper location. It may be easiest to loosen both nuts and screws, remove one of them while noting the positions of each spacer/collar/washer, and replace the screw and nut from the back side to hold everything together. Upon removal of the second screw, the shaft/detent assembly can be slid from the switch decks and rotors CAREFULLY. Inserting the replacement shaft/detent while aligning the flats of the shaft with each switch rotor will be essential. Once inserted, the opposite side screw and nut (the one holding all the decks and spacers/collars/washer together) can be removed from the rear, then re-inserted from the front as it should be.

    It will require a LOT of time and patience, and likely will require forceps, very find needle nosed pliers, and then more patience.

    It may be easier to simply desolder and re-solder each wire. There are only about 20 of them after all.
     
  3. cicada

    cicada Member

    Messages:
    81
    Location:
    New Zealand
    Thanks for your time and support ,
    I will wait to get the replacing part to have a closer detailed look to fully understand what you described so well, I found mesmerising starring at the shaft mount and wires inside the receiver, such a hard spot to work in, if you are familiar with this model, from what side would you tackle this job?
     
  4. cicada

    cicada Member

    Messages:
    81
    Location:
    New Zealand
  5. Watthour

    Watthour Electron Rancher - JS3600

    There will be a lot of disassembly required to expose the switch in either method.
     
  6. Ross Henning

    Ross Henning AK Subscriber Subscriber

    Messages:
    106
    Location:
    Pinehurst, TX (Houston Area)
    I had the same issue with an ax-828. I found it was much easier to replace the shaft rather than re-soldering everything. Take several photos before disassembly in case something gets out of whack. It worked like a charm for me.
     

     

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  7. cicada

    cicada Member

    Messages:
    81
    Location:
    New Zealand
    Replacing the shaft was our final choice, surely the best way to go,
    we have used strategic drops of Loctite glue to keep the selector spacers and rings all together once the long screws were loose,
    replaced the shaft was a breeze this way.
    Feeling happy to have saved this machine, all the rest seems to be in good conditions,

    To the unknown Selector donor amp ex-owner, you are a wise man, I don't know if I would ever be able to make that hard choice,
    bless you where you are, I hope you had few bucks back from the dismantling and got yourself nice new gear or records, you made me really happy,
    and this 727 will fly again.

    Waiting for some bulbs now, will put some pictures up once reassembled all, for what an incredible sound trough headphones!
    Design quirks: Notorious speakers connections yes sure(OMG), but also very close each other L+R rca i/o !
    None of my cables works there...Oh Pioneer...hunting for some vintage cables now...
     

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