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M-60 New Post Wiring

Discussion in 'Yamaha' started by milo63, Jul 3, 2018.

  1. milo63

    milo63 AK Subscriber Subscriber

    Messages:
    315
    Location:
    Everett, WA
    A ratty M-60 with the usual busted speaker terminals, upper corner post separated from the circuit board and a lot of plastic is missing.
    I thought (my first problem) that it would be easy to pop some binding posts in 3"x8" plate and run the wires directly to them. Who needs a circuit board?
    Wrong, the circuit board is more complicated than I thought, as I'm sure you guys know.

    Wisdom?

    Thanks (again).
     

     

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  2. avionic

    avionic " Black Knights " Subscriber

    Messages:
    44,696
    Location:
    Fort Dodge, Iowa
    Its not really that complicated. Looks can be decieving.
     
  3. milo63

    milo63 AK Subscriber Subscriber

    Messages:
    315
    Location:
    Everett, WA
    Let me poke at it again. Initially I thought six speaker wires and a seperate common ground for L/R sides.
     
  4. milo63

    milo63 AK Subscriber Subscriber

    Messages:
    315
    Location:
    Everett, WA
    Thank you once again for your time and sharing your experience.
    I have to dig myself out of another self-inflicted junk pile (jewels are ADS L300C and Kenny KA-8100).

    Gotta take it all.. Need a big organ speaker with bad surround?
     
  5. milo63

    milo63 AK Subscriber Subscriber

    Messages:
    315
    Location:
    Everett, WA
    Blown up print of the speaker wiring schematic*, reading glasses, flashlight, a couple of beers and I have it sussed.

    One question remains, I don't see any visible capacitors but I do see pretty solder spots over holes where caps would be on the schematic. Are they internal to the board?

    Many thanks for the Mouser link, I get overwhelmed with options when I try to find stuff.

    *Thanks hifiengine.com
     
  6. avionic

    avionic " Black Knights " Subscriber

    Messages:
    44,696
    Location:
    Fort Dodge, Iowa
    Maybe there not there. I was looking over the schematics. I forgot I had a parts carcass
    I just did a visual inspection.
    Nope, there not there.
    Sweet.. Makes it even easier.
     

     

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  7. milo63

    milo63 AK Subscriber Subscriber

    Messages:
    315
    Location:
    Everett, WA
    WOOT!!!
    Happy fourth, sir.
     
  8. milo63

    milo63 AK Subscriber Subscriber

    Messages:
    315
    Location:
    Everett, WA
    Garage therapy day.
    I dug a piece of aluminum out of the scrap bin at work and got busy.

    The notch on top is for the rear cover screw. I had to estimate size and sheared it a bit bigger than needed.

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]
     
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  9. milo63

    milo63 AK Subscriber Subscriber

    Messages:
    315
    Location:
    Everett, WA
    Later...with well deserved IPA.

    [​IMG]
     
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  10. avionic

    avionic " Black Knights " Subscriber

    Messages:
    44,696
    Location:
    Fort Dodge, Iowa
    isopropyl alcohol..?:eek:
     
    Last edited: Jul 7, 2018
    milo63 likes this.
  11. avionic

    avionic " Black Knights " Subscriber

    Messages:
    44,696
    Location:
    Fort Dodge, Iowa
    Check that the positive posts are not shorted to the neg posts with your meter before powering it up.
     
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  12. milo63

    milo63 AK Subscriber Subscriber

    Messages:
    315
    Location:
    Everett, WA
    For those following along at home, don't follow me, I'm lost.

    Later last night I put my meter to the traces of the board and came up with this:

    [​IMG]

    As usual, my "assumption" was flawed and I have to redo it.
     
  13. avionic

    avionic " Black Knights " Subscriber

    Messages:
    44,696
    Location:
    Fort Dodge, Iowa
    I'd be looking at the yellow and white wire . Its going to both ground and positive "C" in your diagram.
     
  14. milo63

    milo63 AK Subscriber Subscriber

    Messages:
    315
    Location:
    Everett, WA
    It's very strange but that's how the board is laid out.

    I plan on rewiring to that diagram and doing a DBT prior to the money shot. Trying to make my diagram jibe with the official schematic makes my head hurt.

    All my jacks are isolated from ground.
     
  15. avionic

    avionic " Black Knights " Subscriber

    Messages:
    44,696
    Location:
    Fort Dodge, Iowa
    I have a M-60 here thats all torn down. Give me and hour.
     
  16. avionic

    avionic " Black Knights " Subscriber

    Messages:
    44,696
    Location:
    Fort Dodge, Iowa
    Your right. Doing some confusing switching with the A,B,C speaker select switches. Press on..:D
     
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  17. avionic

    avionic " Black Knights " Subscriber

    Messages:
    44,696
    Location:
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    Due to speaker C being placed in series with either speaker A or B.
     
  18. milo63

    milo63 AK Subscriber Subscriber

    Messages:
    315
    Location:
    Everett, WA
    There you go, thinking...
    I was trying to figure out how to truncate the wiring to one set of speakers (who needs three?) but gave up.

    I broke a banana terminal so I'm on hold until delivery. Plenty of other projects to occupy my time....I don't have time for a job, too many projects to work on.
     
  19. avionic

    avionic " Black Knights " Subscriber

    Messages:
    44,696
    Location:
    Fort Dodge, Iowa
    How did that happen ?
     
  20. milo63

    milo63 AK Subscriber Subscriber

    Messages:
    315
    Location:
    Everett, WA
    Torque....snap.
     

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