sansui ba 3000

Discussion in 'Exclusively Sansui' started by maclvrbr, Oct 3, 2017.

  1. maclvrbr

    maclvrbr Super Member

    Messages:
    1,257
    After the amplifier has been on for approx and hour the speakers develop a high static noise coming through them. This has happened with multiple sets of speakers being used to rule out x-over. Any ideas where to begin diagnosing, thanks
     
  2. vigman

    vigman SUBSCRIBER

    Messages:
    4,020
    Location:
    Valencia CA
    Does it happen with the front volume knobs turned all the way down ? What are you using for a preamp ? What is the history of the amp , recent service , restore.,E bay or found in grandpa's garage special?
     
  3. maclvrbr

    maclvrbr Super Member

    Messages:
    1,257
    I have not checked with volume knobs fully CCW or at zero. I am using a mcintosh mc 28. No history on the amp I acquired a year ago and have been using it one a dy since then. I suppose I could incorporate another amp to rule out the preamp. Ideas?
     
  4. vigman

    vigman SUBSCRIBER

    Messages:
    4,020
    Location:
    Valencia CA
    Running an un serviced BA-3K ( or anything of that vintage ) could be a costly mistake, Checking bias ( and it's stability ) would be a must. If nothing else IF YOU HAVE THE SKILLS.... inspection of the Regulator board ( cold solder joints, clean pins ) and same for the driver board..There are some OL SKOOL semis in the front end that get noisy over time.... These amps are SO GOOD when all is well.. Another note is to find the serial # and somewhere around here is a lookup table for the production build date.. the early ones have additional issues on the driver board. Some of them have extra jumpers between the driver boards and it's mother board to prevent against pin failure.....
     
  5. vigman

    vigman SUBSCRIBER

    Messages:
    4,020
    Location:
    Valencia CA
    If the volume ( actually input pads since there is no gain ) is turned all the way down & the amp is up to temp, and no static, your problem is up stream...
     
  6. MarZutra

    MarZutra Addicted Member

    Messages:
    5,015
    Location:
    New Scotland, Canada
    A decent amp for sure. I'd probably take it in to a tech and get them to give'r a good servicing. At least then you'll be comfortable that it will be AOK and a bonus if/when you sell'er on..
    Good luck and enjoy your Sansui.
     
  7. LBPete

    LBPete Rolling Along Subscriber

    Messages:
    11,007
    Location:
    Long Beach, CA
    The BA-3000 is one of Sansui's best. Please post the serial number for the database. Click on the link in my signature block.

    - Pete
     
  8. Overundr1

    Overundr1 AK Subscriber Subscriber

    Messages:
    2,330
    Location:
    Mississippi
    Unplug the pre amp and see if the static continues
    Will rule out that part of the chain
     
  9. maclvrbr

    maclvrbr Super Member

    Messages:
    1,257
    Thanks for the ideas, Will check bias and dc offsett clean plug connectors as well. thanks Lee will unplug to rule out any other component.
     
  10. JOMARK911

    JOMARK911 Super Member

    Messages:
    2,474
    Location:
    Athens Greece
    I own two of these. Before you do anything else, while static is happening select and deselect subsonic filter a couple of times. Like ON then OFF. If it stops , your problem is in the filter board that lies below the power meters.
    Then we talk.
     
    super98lsc likes this.
  11. maclvrbr

    maclvrbr Super Member

    Messages:
    1,257
    I have let it run without an input for at least 2 hours without issue. I will continue to monitor it however may be looking at my preamp as possible culprit
     
  12. vigman

    vigman SUBSCRIBER

    Messages:
    4,020
    Location:
    Valencia CA
    I would now run an iPod or something external to see if the failure is under load or higher temp....
     
  13. maclvrbr

    maclvrbr Super Member

    Messages:
    1,257
    Ok the issue is definitely in the amp with no input connected . When the static begins the left meter jumps with static. I pushed the filter buttons with no change.
     
  14. vigman

    vigman SUBSCRIBER

    Messages:
    4,020
    Location:
    Valencia CA
    Rebuild time !
     
  15. maclvrbr

    maclvrbr Super Member

    Messages:
    1,257
    I would like to isolate the issue in the left channel first
     
  16. vigman

    vigman SUBSCRIBER

    Messages:
    4,020
    Location:
    Valencia CA
    1st yo have to check if there have been EXTRA wires soldered to your 2705 board... do you have the schematic?
     
  17. maclvrbr

    maclvrbr Super Member

    Messages:
    1,257
    S/N 245060187
     
  18. maclvrbr

    maclvrbr Super Member

    Messages:
    1,257
    Do you mean 2507 board? I do have a schematic.
     
  19. vigman

    vigman SUBSCRIBER

    Messages:
    4,020
    Location:
    Valencia CA
    Some " repair " shops added extra wires between the 2512 board and the 2507 to make up for possible pin failure... If you have those wires you cannot remove the 2507 for bench testing / visual inspection.
     
  20. maclvrbr

    maclvrbr Super Member

    Messages:
    1,257
    There are no wires added to this board. I will remove and check all solder joints ( reflow) and clean pins at connector joints.
     

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