sansui z9000 output issues help!!

Discussion in 'Exclusively Sansui' started by musical maze, Sep 5, 2017.

  1. musical maze

    musical maze Member

    Messages:
    82
    hi folks having issues whenever I turn up the volume the relay trips
    if I turn it back down its fine of course this beast is as old as the hills and still sounds good,would sure like some help from my fellow akrers.
    thx.
     
  2. kevzep

    kevzep Its all about the Music Subscriber

    Its actually probably pretty straight forward to fix, I had a AU417 in last week doing the same thing.
    Just turned out to be a couple of fusible resistors which had severely drifted in value.

    I'll have a peek at the schem, and see what the story is....
     
  3. kevzep

    kevzep Its all about the Music Subscriber

    Unit uses STK output modules which is interesting, but good.

    There are a number of resistors in the power amp driver section that should be checked.
    Get the schematic from HiFi Engine and get into it with your DMM...
     
  4. Robisme

    Robisme Sansui Enthusiast Subscriber

    Messages:
    11,802
    Location:
    Martinez California
    That would be interesting as the Z9000X uses output transistors. STK predriver.

    Edit: I can't find a schematic for the Z9000, but it may be similar to the Z9000X.

    See this. On the page, click on "if you want to view data sheet, click here"

    Where do the meters hit when it trips? 4 ohm or 8 ohm speakers?

    Disconnect the speakers and see if it does it? If not, connect one at a time and see what happens. As in right only, then left only.

    Check DC at speaker terminals.


    Rob
     
    Last edited: Sep 5, 2017
  5. kevzep

    kevzep Its all about the Music Subscriber

    My mistake, there is a STK3106 in this amp, but not what I thought is was........Thanks for pointing that out Rob, sometimes we make mistakes.
     
  6. Tom B

    Tom B AK Subscriber Subscriber

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    Location:
    Bay Ridge, Brooklyn New York
    Hopefully the issue isn't the STK3106 because they are real hard to find, and can be expensive.
     
  7. musical maze

    musical maze Member

    Messages:
    82
    thx for the reply folks. ill do some checks and update.it does not trip when the speakers are diconnected
     
  8. musical maze

    musical maze Member

    Messages:
    82
    it trips on both channels even if I connect one speaker to to each channel at a time
     
  9. kevzep

    kevzep Its all about the Music Subscriber

    The protection will be common to both channels, so you wont find out which channel it is by doing it that way.

    Have you gone in and measured the resistors like we suggested? I can say with certainty you will find the fusible resistors in the driver circuit will have drifted and are causing this issue.
     
  10. Robisme

    Robisme Sansui Enthusiast Subscriber

    Messages:
    11,802
    Location:
    Martinez California
    If it does not trip with the speakers disconnected, which it does not, and the problem is an over current in one channel with the speakers connected, then you most certainly can determine which channel is causing it to trip into protection by connecting one speaker at a time.

    That said, it looks like that's not the problem.

    Still want to hear what impedance your speakers are and what the meters read when it cuts out.

    The service manual seems to be no help in identifying the fuse resistors. You will just have to test them all if you can't tell which ones are FRs by looking at them.

    Rob
     
  11. kevzep

    kevzep Its all about the Music Subscriber

    To the OP good place to start is with any resistors which are low in value, between about 4.7-200Ω, they are usually of a "sandy" type appearance, grey, red, and with the "s" bend in the legs and standing up off the board, around the pre drivers and bias circuit....
    On the schematic, there are what looks like "!" in a triangle, perhaps this is indicating something to do with fusible resistors..
    In any case they will be in there and you just basically need to get you multi-meter and start measuring.
    It will be obvious which ones are bad, they will read in the MegΩ range or high KΩ at least
     
  12. Robisme

    Robisme Sansui Enthusiast Subscriber

    Messages:
    11,802
    Location:
    Martinez California
    So I pulled my Z-5000X open to see about fuse resistors. There are plenty, so there are probably plenty in your Z-9000.
    But I also noticed something that may also cause problems. The corrosive glue. My Z-5000X has a lot of it as well as many corroded component leads.
    You may want to look for that while you're in there.

    Rob
     
  13. musical maze

    musical maze Member

    Messages:
    82
    folks thx for the suggestions will do checks and update as I not at home since our last correspondence
    cant wait to apply the advise given.
    thx again for your input with this problem.
     
  14. musical maze

    musical maze Member

    Messages:
    82
    so folks did some checks only to find out it was my speakers that
    was causing the problem,thx again for you advise it is always appreciated.
    connected another speaker ,no issues,guess ill have to figure out what is causing
    the speakers to short.any ideas.
     
    Last edited: Sep 20, 2017
  15. LBPete

    LBPete Rolling Along Subscriber

    Messages:
    10,932
    Location:
    Long Beach, CA
    Glad to hear you found the problem. Please post the serial number for the database. Click on the link in my signature block.

    - Pete
     
  16. musical maze

    musical maze Member

    Messages:
    82
    will do pete
     

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