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DC offset at output - 18 volt. What componet is faulty?

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  • gpinchik Oct 01, 2008

    ONKYO A -8190 amplifier.I can email you circuit diagram ASAP. minus 18 volt output.

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  • Master
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Hi,

Re your post "...I can email you circuit diagram ASAP..." perhaps you could post/upload the schematics to http://megashares.com/ and thereafter post the link here.

Initially,

  • have you checked the the counterpart, +18?
  • have you measured the voltages without load?
  • it could be not a power supply problem but the outputs loading the PSU.
Hope this be of initial help/idea. Pls post back how things turned up or should you need additional information.

Good luck and kind regards. Thank you for using FixYa.

Posted on Oct 01, 2008

  • Louie  Role
    Louie Role Oct 01, 2008

    Hi again,

    There are four (4) versions of an Onkyo A-8190: UD, UG, UQ and UW/UWX. The difference mainly is on the power supply section. But what is common is TA7317P (protection IC), Q701, you may want to start there or the output transistors 2SA1491 & 2SC3855.


  • Louie  Role
    Louie Role Oct 06, 2008

    Hi again,

    Got the schematics that you provided. A question pls, at what point did you measure the -18VDC, speaker terminals?

    If yes, then most likely a problem with the output transistor pair as initially posted. Additionally, if it is only on one channel, then you can use the other channel as reference when doing voltage measurements or in passive/resistance checks.

    Good luck and pls postback updates.


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CAn you please inform us what is the model and brand of your unit so we can help you better...

Posted on Oct 01, 2008

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