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Basic CD player in a micro music centre

Discussion in 'Electronic Repair' started by N Cook, Sep 24, 2007.

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  1. N Cook

    N Cook Guest

    No movements or laser light , totally dead CD player. Just -- in the
    Function sw and door latch sw ok. Plenty of 5V etc supplies around on the
    chippery. Crystal and ceramic resonator have oscillation.
    All 4 channel motor/focus driver o/p at 3.8V, all 4 inputs at 2.1V, disable
    is set off ie operational.
    Pressing all sm chip leads , no change
    Swapping laser and carrier/motors section with another one laying around,
    the same zilch. No dodgy electrolytics.
    Is there something obvious I'm overlooking ?
    Not worth spending a lot of time on but a good customer for other stuff.
  2. Arfa Daily

    Arfa Daily Guest

    Can't think of anything that you seem to be overlooking. First place I would
    have gone is the same as you - to the door switch. Even though the switch is
    working ok in itself, I would still feel inclined to make sure that its
    connections are making it all the way back to the micro, and doing something
    ie pulling a pin to ground or whatever. I've had internal pull-up resistors
    on micro pins fail. The only other thing that it's worth doing when all else
    has failed, and you've given up, is to try a possible 'real' system reset,
    by holding in the power button and applying power, and if that fails, a
    'naughty' engineer's reset, by turning off and removing power, then hooking
    a croc lead to ground, and stroking round every pin of every 'micro-ish' IC
    both on the front panel, and the CD process board. I've known this to
    restore screwed up system controls on a number of occasions. I got it
    originally from a manufacturer's training course, but so far back in the dim
    mists of time, I can't remember which one now ...

  3. Don't forget the sled limit switch - brand and model info might help.

    Mark Z.
  4. N Cook

    N Cook Guest

    Perhaps stripping off at midnight and dancing around it on a full moon might
    work as well.
  5. Arfa Daily

    Arfa Daily Guest

    Only if it's a Philips ...

  6. Meat Plow

    Meat Plow Guest

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