Panasonic DMR EX77 FAULT

Discussion in 'Blu-ray & DVD Players & Recorders' started by splive, Dec 22, 2011.

  1. splive

    splive
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    I have a DMREX77 that worked fine for a couple of years but then developed a weird fault which is a little difficult to describe:
    When viewing from any AV source, ie. recording from a scart input, the picture is fine, but the audio has the terrestrial input (RF) bleeding over it.
    I live in Spain, took it to a local Panasonic authorised dealer who had it for a couple of weeks and then said one of the main boards has blown and replacements are no longer available.
    I've now donated it to my Dad who has already replaced capacitors on another faulty Panasonic machine and fancies having a go at repairing this one.
    Any pointers or ideas where to start greatly appreciated.
     
  2. Gavtech

    Gavtech
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    Welcome to the forum.



    Sadly - it is almost certainly beyond repair ... unless your Dad is exceeedingly skilled and patient... and this means skilled beyond the capabilities of almost all repair engineers.

    The culprit will be IC3001 ... which is the main audio and video processing chip which also takes care of signal routing and switching.


    This is a 100 pin chip with microscopic pins.
    The chances of being able to remove it without damaging the board or damaging the replacement chip are low.

    Such chips, if they are ever replaced, are done using very expensive professional equipment.
    Even then it is regarded as a risk and that you are lucky if it works.

    If you wish to persist, your best course of action is to obtain a spares or repair machine to get the main board out of that ... but this is not straightforward either.

    I cant remember the details but there are eeprom issues to consider.

    The machine is probably best used in its current state and using workarounds... such as tuning to a 'non station' when recording from an AV source so that no audio bleed-through is present.
     
  3. splive

    splive
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    Gavtech, thanks for such a quick and comprehensive reply. I think the repair you mention is probably beyond my Dad's capabilities. Is the chip not on a board that could be replaced? Extremely disappointed with Panasonic too as I don't expect this sort of premature failure from a decent brand.
    Thanks again for you help.
     
  4. Gavtech

    Gavtech
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    The chip is on the main board... the one that comprises the whole area of the machine.

    I don't think Panasonic can be held responsible for this. This is a chip that has shown its vulnerability across many machines.
    I don't know who the chipmaker is, (Edit - It is a Sanyo chip) but it is doubtful that they can be termed responsible either. The vulnerability that exists is just because of the nature of physics.

    Also, Panasonics instructions for use will cover this because, almost certainly, this kind of problem arises from static discharges coming down cables that are attached to the machine... and that chip is connected to every input and output on the machine.

    The more inputs and outputs a machine has the more vulnerable it is... and Panasonics always have many.

    Users rarely do as the instructions say - which is make all connections with the unit unpowered before switching on which should prevent this kind of problem from occurring.

    It's just bad luck.


    As an aside, some years ago when TV's still had wooden cases, I killed a TV just by leaning on the top of it when wearing leather gloves... having just walked across a carpet.
    Where my knuckle pressed into the leather, it thinned it out enough for a discharge to occur... I felt a jolt as I discharged into the set... and the TV snuffed out.

    I'd killed one of the main chips in the set.
     

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