B-1 Quickie

Discussion in 'Yamaha' started by rottalpha, Dec 11, 2017.

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  1. rottalpha

    rottalpha Yamaholic Subscriber

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    will scan it for ya
     
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  2. vintagejapan

    vintagejapan AK Member Subscriber

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    Fantastic,

    Cheers. :D:thumbsup:

    Those are nice heatsinks :idea: What will special permission cost me?
     
  3. rottalpha

    rottalpha Yamaholic Subscriber

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    makes a good Sunday afternoon read,

    or if you were to rebuild your B-1, this probably has more info than other places on the net....
    I had a hard time finding info on B-1 rebuilds when I decideed to take on the "quickie"
     
  4. rottalpha

    rottalpha Yamaholic Subscriber

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    I am thinking maybe you could find out for us if those C rank SK180s of yours need further matching
    In the meantime, "technical" details of my patented heatsinks are somewhere on the first page of this thread, in my response to Bratwurst.
     
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  5. vintagejapan

    vintagejapan AK Member Subscriber

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    Thank you Pete,

    Am waiting for some parts and should be firing up the beast soon.
    I have just completed the power supply boards 1&2.

    Will let you know how I go
     
  6. vintagejapan

    vintagejapan AK Member Subscriber

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    I also had a faulty MPSU60 on the power supply board 2 which I replaced this with a MPSW92.
     
  7. vintagejapan

    vintagejapan AK Member Subscriber

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    Had to cut the heatsink for it, it is not much space in there
     

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  8. rottalpha

    rottalpha Yamaholic Subscriber

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    that would work.
     
  9. vintagejapan

    vintagejapan AK Member Subscriber

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    Well, the capacitor kit from Clinic is in. I have finished the power supply boards 1&2. A quick test and the-200 volt and +40 are showing up nice and steady on the power supply board #2. Also managed to adjust the 12v, -25 and +25 on power supply board #1. I have a weird issue though. When I turn off the power switch the amp stays on for few seconds. Then turns off. Not sure what to make of it.
    I checked the switch and the connection with the UC-1 and found no issues.
     

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  10. rottalpha

    rottalpha Yamaholic Subscriber

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    That main caps kit sure looks nice.:thumbsup:

    I think you are on the right track with troubleshooting. I would look at the switch and the protection circuit, including that solenoid.

    the question I have is how were you able to adjust the voltages if the power turns off so quickly??

    FYI, I powered averything up with a DBT and a variac, all the way to the driver boards.
     
  11. vintagejapan

    vintagejapan AK Member Subscriber

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    I think the power switch may be the culprit.

    When I turn the power ON remains on, but when I turn the power OFF just lingers for a couple of seconds before the power cuts off.
    The 3rd protection board is in, now the real fun begins...
     
  12. rottalpha

    rottalpha Yamaholic Subscriber

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    Say a prayer or two first, then watch those test leads.
     
  13. rottalpha

    rottalpha Yamaholic Subscriber

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    What's taking so long:D
    Now I get to ask that question :beatnik:
     
  14. vintagejapan

    vintagejapan AK Member Subscriber

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    Well, the protection test went well last night.
    Just finished the filter board.
    Used 2SC1815 and 2SA1015 to replace the C458 and A763 transistors. Still need to source the relay.
    Also replaced some of the ceramic caps with silver mica.


    Pondering now on the first drive board.
     

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