Sansui B2101 - DC voltage gone crazy 10V++ and something missing on board.

Discussion in 'Exclusively Sansui' started by Steven Sze, Oct 4, 2017.

  1. BigElCat

    BigElCat AK Subscriber Subscriber

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    The board with the white wires is the left channel power board.

    The black wires in Avionic's picture go the right channel power board.

    The boards are identical...not mirror images.

    The red and blue power wires do not land on the same traces. Left channel is different from right channel regarding where the power wires attach.

    My pictures all have the left channel showing.

    Thanks Hyperion. I wouldn't have noticed this difference if you hadn't said something.

    I'm not planning on working on my B-2101 any time soon.
     
    Last edited: Oct 11, 2017 at 4:16 PM
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  2. Steven Sze

    Steven Sze New Member

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    Ah.... I see. I connected the blue and red wire the same for both channel.. After I made these connection.. I powered up the amp.. measured the TP on 4618 board , on the left channel I manage to adjust it to about 100mV ( huge improvement from 10V but on the right channel the reading only moves between 1.7V and 1.9V .. way way above the -+5mv. Can you show me the right channel when you're free, Im kinda curious why blue red wire is on different trace on board when both is identical board..

    Ps: sorry for the slow reply, i was travelling for work past couple of days.
     
  3. BigElCat

    BigElCat AK Subscriber Subscriber

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    Sorry this thread is so choppy. I'm on my way out the door, now.

    I still have the covers off. I'll get some pics of the right channel tomorrow (?)

    I'm not sure the red and blue wires are "power wires"...and don't know why they go to different "landing spots".
     
  4. Steven Sze

    Steven Sze New Member

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    BigElCat , photo of the right channel would be great :)

    Btw I notice that your 4618 board (the vertical board at the front panel) is placed upside down.. if you want to adjust the dc offset in the future you'll need to put it back at the right position.. I'll post a photo of it later.
     
  5. BigElCat

    BigElCat AK Subscriber Subscriber

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    We were looking at it from the bottom in the previous pic.

    Here they are from the top. All the VRs point for access from the top.

    DSC00408.JPG

    I have some of the right channel "power wires" in a few minutes.
     
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  6. BigElCat

    BigElCat AK Subscriber Subscriber

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    The right channel...the top of the photos is toward the front panel of the amp.
    DSC00409.JPG
    DSC00410.JPG
    DSC00411.JPG
     
  7. BigElCat

    BigElCat AK Subscriber Subscriber

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    My pics aren't very good...but these are factory solder joints.

    This amp did come out of protection mode a couple of times.

    I need to set the bias and DC offset.
     
  8. BigElCat

    BigElCat AK Subscriber Subscriber

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    Here's the left channel...top of pic is toward the front panel of the amp.

    This is the F-4619 board, but it's rotated 180 degrees compared to the other side.

    The two opens holes near the center of the pic are where the wires attach for the right channel.

    At least that's how it is on my amp.

    DSC00414.JPG
     
  9. Steven Sze

    Steven Sze New Member

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    Thanks for the photos man.. really appreciate it.
     
  10. Steven Sze

    Steven Sze New Member

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    You'll have to start with the 2 pin Test Point on the 4618 board.. -+5 mV.. followed by

    Currently mine is reading 100mV and 1.7V.. cant remember which channel..
     
  11. BigElCat

    BigElCat AK Subscriber Subscriber

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    There are three VRs on each 4619 board.

    Which one do I adjust ?

    What do the other two on the 4618 board do ?
     
  12. avionic

    avionic " Black Knights" Subscriber

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    Aren't you using a service manual ???
     
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  13. avionic

    avionic " Black Knights" Subscriber

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  14. Steven Sze

    Steven Sze New Member

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    This power amp is a bit different. You'll have adjust 5.

    20171013_103354.jpg
     
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  15. Steven Sze

    Steven Sze New Member

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    All 5 will be used to adjust dc and bias..

    20171013_103259.jpg
     
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  16. Steven Sze

    Steven Sze New Member

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  17. BigElCat

    BigElCat AK Subscriber Subscriber

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    Ok...I'll do it this weekend.

    You guys rock !

    I can't remember my log-in stuff for HiFi Engine. I tried to log in a couple of months ago and failed. I don't remember the specifics right now, but it wasn't as simple as resetting my password.

    I guess I better check into that, too.
     
  18. Steven Sze

    Steven Sze New Member

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    https://elektrotanya.com/sansui_b-2101_sm.pdf/download.html

    I always find for service manual from elektrotanya.. click on the link above.
     

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