B-2101 repair project.

Discussion in 'Exclusively Sansui' started by BigElCat, Jan 2, 2018.

  1. BigElCat

    BigElCat Mmm Hmm Subscriber

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    The back story. I bought this amp on Etsy. They said it worked fine, but it was reluctant to come out of protection. It would turn on, but sounded rather lame. Eventually, it wouldn't turn on at all.

    I put it on the shelf for a while. I tried the set the Bias, and blew out a Sanken.

    http://audiokarma.org/forums/index....-missing-on-board.790817/page-3#post-11075220

    So I'm starting the disassembly. This will be slow, I haven't ordered any parts.

    Thought I'd post a few pics.
     
    Last edited: Jan 2, 2018

     

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  2. BigElCat

    BigElCat Mmm Hmm Subscriber

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    Had to take the top and bottoms covers off.
    The F-4619 board comes out with the big heat sink attached.
    I'm only going to work on the right channel for now.
    WIN_20180102_03_50_00_Pro.jpg WIN_20180102_03_55_23_Pro.jpg

    Time to break out the Hakko and desolder bulb.

    DSC00440.JPG DSC00441.JPG DSC00442.JPG
     
    Last edited: Jan 2, 2018
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  3. BigElCat

    BigElCat Mmm Hmm Subscriber

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    I want to replace kVR3 and kVR4 with Bourns multi-turns.

    The are 1K ohm, but no wattage rating is given in the service manual.

    Any suggestions ?

    This is for me...I think I'll order from digi-key.
     
    Last edited: Jan 9, 2018
  4. Hyperion

    Hyperion Roobarb & Custard Subscriber

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    BigElCat and SansuiJavier like this.
  5. SansuiJavier

    SansuiJavier AK Subscriber Subscriber

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    I also used the bourns 3296 of 1/2 W ..
     
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  6. BigElCat

    BigElCat Mmm Hmm Subscriber

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    Thanks guys. They're in my cart.
     
    Last edited: Jan 9, 2018

     

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  7. BigElCat

    BigElCat Mmm Hmm Subscriber

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  8. Hyperion

    Hyperion Roobarb & Custard Subscriber

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    I'd rather buy my own - you don't know what rubbish your going to get in that kit.
     
    Last edited: Jan 9, 2018
  9. Hyperion

    Hyperion Roobarb & Custard Subscriber

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    Looks right to me.
     
    Last edited: Jan 9, 2018
  10. SansuiJavier

    SansuiJavier AK Subscriber Subscriber

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  11. BigElCat

    BigElCat Mmm Hmm Subscriber

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    I'll order caps individually. Shall I use Panasonic FCs for the Power Amp Board ? IIRC, that's what I did in my AU-X701.

    What about this big resistor that was smoked up when the Sanken blew ?

    WIN_20180103_15_34_22_Pro.jpg
    WIN_20180103_15_35_04_Pro.jpg

    It should be okay, don't you think ?
     

     

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  12. SansuiJavier

    SansuiJavier AK Subscriber Subscriber

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    .
     
    Last edited: Jan 6, 2018
  13. BigElCat

    BigElCat Mmm Hmm Subscriber

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    The Panasonic FCs only have a 1000 hour life. That seems really low.

    Digikey only has them to replace this one.

    WIN_20180103_15_41_38_Pro.jpg

    I'll need to substitute a Nichicon or something for the 10uF 35v ones. Or shop somewhere else.

    I appreciate your help guys. I have to go to work now...I'll check back tomorrow.
     
  14. avionic

    avionic " Black Knights " Subscriber

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    Not using mini-grabbers..:idea: Looks like the emitter lead vaporized.
     
  15. BigElCat

    BigElCat Mmm Hmm Subscriber

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  16. BigElCat

    BigElCat Mmm Hmm Subscriber

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  17. BigElCat

    BigElCat Mmm Hmm Subscriber

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  18. BigElCat

    BigElCat Mmm Hmm Subscriber

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    I did 2-1; steps 1 and 2

    Then 2-2; steps 1 and 2.

    Then on 2-2; steps 3 and 4....I got no response from the DMM while trimming kVR2.

    It must have been reading all zeros, with no response when I moved the VR.

    I skipped to 2-2; steps 5 and 6. (I called that the "3rd adjustment").

    I shouldn't have done that...messed with the Bias Current Adjust after I cranked on kVR2 .
     
  19. BigElCat

    BigElCat Mmm Hmm Subscriber

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  20. BigElCat

    BigElCat Mmm Hmm Subscriber

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    Here's my right channel F-4619 board. Service manual says the ground pin is furthest away from Sankens.

    DSC00445.JPG

    SansuiJavier confirms the manual is correct...the ground pin is furthest away.

    So I don't know what I did wrong.

    Someone has offered to send me a couple of used Sankens to try. I'm going ahead and order the Bourns and some caps.
     
    Last edited: Jan 4, 2018

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