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Toshiba DVD SD-3109U weak audio

Discussion in 'Electronic Repair' started by billccm, Dec 22, 2006.

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  1. billccm

    billccm Guest

    Hello All:

    I have a Toshiba DVD player, model SD-3109U. Both L and R channels have
    really weak audio with some slight distortion.

    I pulled the circuit board near the rear of the unit where the RCA
    phono connectors are mounted. Solder looks good, and there is not much
    on this PCB active components wise.

    Any idea where to look? I assume since both L and R channels are both
    weak, it is in a common device somewhere.

    I would really like to fix this DVD player; it is my favorite in the
    house.

    Thanks for any help, and Merry Christmas to all!

    Bill
     
  2. Jerry G.

    Jerry G. Guest

    The only way you are going to be able to troubleshoot this is to buy
    the service manual, get a good scope and DVM, and the calibration CD,
    and start troublshooting the player. If you are not experienced in
    troubleshooting CD players and have a solid background in the theory at
    the component level, it will be a struggle to go through it.

    It would be more feasible for you to give the player over to the
    authorized service rep for Toshiba. You may find it expensive to
    service in relation to replaceing it.


    Jerry G.
    ======
     
  3. Arfa Daily

    Arfa Daily Guest

    Is the display OK ? One of the Tosh models from a couple of years ago, but I
    can't remember exactly which one, used to suffer from the decoupling caps on
    the + / - 12v rails that feed the audio out buffer amp, going short circuit.
    I seem to recall that if the one on the "+" rail went, you got no or v.low
    audio and no display, and if the one on the "-" rail, just no audio. I
    think on that model, there are two or three little 8 pin opamps that buffer
    the audios on the ouput board, and the caps in question are a couple of
    100uF electrolytics.

    But before you start getting too technical with it, just check in the menus,
    that no one has accidentally changed the audio mixdown on it.

    Arfa
     
  4. billccm

    billccm Guest

    Thanks for the replies. I took all three PCBs out and inspected the
    solder under the mircosope; looks good. There are a few MSOP and SOIC 8
    pin devicews on the output PCB, and LOTS OF Electrolytics!
    I am going to call a local repair shop to see if they fix these things.
    Since the unit is entirely surface mount, with some really high pin
    count TQFP devices, I wonder how a repair shop can even change out
    components in these things now days.
    Have a safe, and happy Holiday ALL,
    Bill
     
  5. David Naylor

    David Naylor Guest

    Hi there
    I work for a service center, but it has been a long time since i
    have worked on a DVD player. but as i remember, the toshiba with weak
    audio was a common problem it was cause by a shorted Electroletic cap
    in the power supply check them all i think it was c 528 and 529
    But nat really sure.. as i said check them all.. and the thing was you
    could just cut the thing out and the unit would work fine. i was a
    service buliton and that was the fix good luck
     
  6. Franc Zabkar

    Franc Zabkar Guest

    FWIW, here is a service manual with circuits:
    http://www7.toshiba.com/secured/tass/technical/dvd/SD5109.pdf

    - Franc Zabkar
     
  7. Ken G.

    Ken G. Guest

    I dont remember models either but the Toshiba problem ones had a small
    sized case .
    There were 4 small capacitors over near the input/output jacks that were
    to small of voltage rating . It is confusing because there are quite a
    few caps in the spot .

    The caps would turn into resistors and mute the sound . I fixed about 8
    of these till i stopped seeing them come in . In some of them i was able
    to get it to jump back on by being fairly aggressive pushing , bending
    and pulling on capacitors then replace it .
    I used to have the board part #`s but lost it .
     
  8. billccm

    billccm Guest

    Thanks for the schematic! I will trace the audio tonight!

    I'll let you know what I find. Thanks again, and Merry Christmas to
    all, Bill
     
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