CR-800 preamp cap mod

Discussion in 'Yamaha' started by sssboa, Feb 12, 2018.

  1. sssboa

    sssboa Well-Known Member

    Messages:
    606
    I have 2 units of CR-800. I noticed a difference in preamp. In one there is a striped film cap (pic1) instead of ceramic (pic2). Someone's mod I guess.
    Can anyone read the stripe code on that film?
    I cannot find that cap on schematics to read the value, it's c531.

    cap1.jpg cap2.jpg cap3.jpg cap4.jpg
     

     

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  2. Katalyst

    Katalyst AK Subscriber Subscriber

    Messages:
    635
    Location:
    Indianapolis, Indiana
  3. Katalyst

    Katalyst AK Subscriber Subscriber

    Messages:
    635
    Location:
    Indianapolis, Indiana
  4. Katalyst

    Katalyst AK Subscriber Subscriber

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    635
    Location:
    Indianapolis, Indiana
    What is the difference between the two?
     
  5. sssboa

    sssboa Well-Known Member

    Messages:
    606
    so seems to be 0.1uF, still can't find it on the schematics.
     
  6. mbz

    mbz AK Subscriber Subscriber

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    1,953
    Location:
    Melbourne, Victoria
    Looks like the cap between R541 and R545 on the schematic.
    C529 and C533 are in the neighbourhood. The artwork shows it's
    connected to FR651 and FR502, so it goes from rail to ground,
    so just a high freq/RF noise path
     
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  7. sssboa

    sssboa Well-Known Member

    Messages:
    606
    Yeah, deduction.
    I will replace this cap cause it's cracked, I painted it with silicon. Hope 0.1uF value is ok. It is a mod, isn't it? It should be ceramic disk rather. I don't want to pull the ceramic from my other unit just to check the value, cannot see it from the other side without dismantling tone board.
     
  8. mbz

    mbz AK Subscriber Subscriber

    Messages:
    1,953
    Location:
    Melbourne, Victoria
    I'd go with a 0.1uf ceramic. The CR1000 has a 0.1uf cap (C499) in this position. It is just a noise path so ceramic is fine.
     
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  9. sssboa

    sssboa Well-Known Member

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    606
    I ordered 0.1uF film already, should be ok.
     
  10. rcs16

    rcs16 Super Member

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    Location:
    Baldwin, Ontario, Canada
    I do not know why you want to change those film/disk caps, they will probably out last you.

    Did you change C502?) in left pic that I see (1uF/?) orange and yellow. better to replace with a 1uF film in a 5mm lead space, really does not matter the brand, just 1uF, 50+ DCV
     
  11. sssboa

    sssboa Well-Known Member

    Messages:
    606
    I replace them films if they are damaged.
    I replaced the orange tantalum 1uf/25v with yellow 1uf/50v tantalum Kemet. There are loads of tantalum caps in these old Yamahas.
     

     

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