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Marantz cassette deck LED failure

Discussion in 'Troubleshooting and Repair' started by Lance Lawson, Jul 1, 2011.

  1. Lance Lawson

    Lance Lawson

    2
    0
    Jul 1, 2011
    Hi I'm glad I found this forum! I have a Marantz SD 3020 cassette deck that I blew out the left LED meter in. This happened due to my screw driver shorting the variable resistor that controls the fine setting levels. The meter still works on input if the left channel is cranked up really high but very distorted due to the huge gain needed to get the LED to respond. Unfortunately I don't have an exact service manual for this deck but I have one for the next one up in the series (SD 4000) which is very similar. If I can locate the parts on the board that need replacing I can install them no problem but I don't have a reliable place to start.
     
  2. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,206
    2,695
    Jan 21, 2010
    OK, provide a link to the service manual if you can (or a scan of the appropriate part of the circuit diagram), and also take a *sharp* photo of the area around where you shorted stuff out. If this is on a printed circuit board, then a picture of the other side of it (the same area) could also be useful if you can easily obtain it.

    My best (and hopeful) guess is that you've damaged a transistor or something which is amplifying the input signal. If that is the case then it may be a relatively simple repair. If the signal goes into some sort if IC then you may have a somewhat harder time.
     
  3. Lance Lawson

    Lance Lawson

    2
    0
    Jul 1, 2011
    Hi Steve here's the board and the area where the short happened. The left variable resistor shorted against the tall heat sink device. BTW the unit still records and plays normally on the normal line outputs. However the left channel of the headphones died when the LED died. The multi connector that's in the foreground go to the LED meter.

    This link will take you to the manual. I have this manual as a PDF from same link.

    http://www.hifiengine.com/manuals/marantz/sd4000.shtml

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    Last edited: Jul 1, 2011
  4. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,206
    2,695
    Jan 21, 2010
    OK, I've had a brief look at the manual.

    I can't locate R289 (which appears to be the trimpot on the right. I assume the other one is R189 (it is obscured). And what is the transistor (I'd be expecting Qxxx)?

    Only had a quick look, perhaps you can find this information and even locate the same named components in the service manual. (they may be different though -- it is a different model)
     
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