ca-810

Discussion in 'Yamaha' started by Willy6, Nov 16, 2017.

  1. Willy6

    Willy6 AK Subscriber Subscriber

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    I recently aquired a yamaha ca-810 that does not power up I currently have it dismantled and ready to work on. The left channel outputs are both shorted but the right channel outputs are still good.
    Does anyone have a parts replacement list for this amp? Any help will be greatly appreciated.
     
  2. Willy6

    Willy6 AK Subscriber Subscriber

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    Is this a fuse resistor?It reads O.L M ohms on my meter. 20171116_024531.jpg
     
  3. mbz

    mbz AK Subscriber Subscriber

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    According to SM HW-20468 is a 68ohm, 85mA fusiable resistor. OL is not good, so you've found a problem. Where was it removed from.
     
  4. mbz

    mbz AK Subscriber Subscriber

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    OK, got it, FR409
     
  5. mbz

    mbz AK Subscriber Subscriber

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    As a general precaution you should also check TR421,3 and D417
     
  6. Willy6

    Willy6 AK Subscriber Subscriber

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    I plan on recapping and replacing any bad components and putting new multi turn trimmers in.What would be a good replacement for the fuse resistors? I'm counting eleven of them on the left and right channel main amp board
     
  7. Willy6

    Willy6 AK Subscriber Subscriber

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    This transistor is shorted also stuck in the middle of some corrosive looking old glue. 20171116_120056.jpg 20171116_120041.jpg
     
  8. mbz

    mbz AK Subscriber Subscriber

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    You only need to replace those that have drifted out of spec, +20%? Replacement options are becoming scarce Yageo FRM25 (0.25W) and FRM50(0.5W) are at
    Mouser in a reasonable value range. Remember, it's a fuse so don't up the wattage. I'd be reluctant to replace a FR with an ordinary metal film but sometimes there
    is no choice. Mount FR's/metal films well above board.

    The board looks ugly but will clean up ok. The CA-810 is supposed to be a nice sounding amp. Got a CA-800 and a CA-1000 both refurbished and sound good.
     
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  9. mbz

    mbz AK Subscriber Subscriber

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    You should check if you have any of those polar tantalums in the phono and preamp. Nichicon KL or MKS being the preferred replacement
     
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  10. avionic

    avionic " Black Knights " Subscriber

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  11. avionic

    avionic " Black Knights " Subscriber

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  12. jheu02

    jheu02 AK Subscriber Subscriber

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    When you're thinking about replacing the trimmers, realize that the ones used originally had an adjustment slot on the bottom of the trimmer also. There are holes in the circuit board to make it easier to adjust them for setting bias, meters, and 25V rails.

    Post #38 of my restoration thread shows the test points and trimmer holes in the CB.
     
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  13. avionic

    avionic " Black Knights " Subscriber

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    Need to erradicate all the old glue..
     
  14. avionic

    avionic " Black Knights " Subscriber

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    Looks like you need to take a long bristled brush.I use and paint brush. And either compressed air or Vacuum cleaner to the boards component side.
     
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  15. Willy6

    Willy6 AK Subscriber Subscriber

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    I found these Panasonic 15000uf 80v caps in my arsenal they are 40mm around by 80mm tall and the originals are 12000uf 58v 40mm around and 70mm tall. 20171116_193215.jpg
     
  16. avionic

    avionic " Black Knights " Subscriber

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    Will they fit with the wooden bonnet ?
     
  17. Willy6

    Willy6 AK Subscriber Subscriber

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    Im not sure yet but if i use them it wil be after i get everything else done and the unit put back together.
     
  18. Willy6

    Willy6 AK Subscriber Subscriber

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    Are there any transistors in this amp that are known problem makers?If not i'll leave them alone and just replace the bad ones.
     
  19. mbz

    mbz AK Subscriber Subscriber

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    Didn't see any red flags. Checked against that list/thread that's circulating, no 2SC458, 2SC1345 etc,,,
     
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  20. Bert 1100

    Bert 1100 Super Member

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    They will not fit. I used Kemets at 75 mm and they just barely clear the selector shafts. You've posted in my thread so you can look at the details there :)
     
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