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finding the radio power pins

Discussion in 'Electronic Repair' started by netvoy, Oct 18, 2005.

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  1. netvoy

    netvoy Guest

    I am trying to find the power pin (Battery +12) and the Ignition pin
    (12v switched --aka ON when key is turned) on a Subaru Panasonic radio
    (p421 --must verify model). I don't have wires on the unit but I can
    make them; the color code would be useless without a plug diagram so I
    can't use that.

    I have not found a site with the diagram on this one as apparently
    Subaru somehow became Mazda?....

    To quote an old message from --sam '96:

    "Locate the power - there will be a +12 switched and possibly a +12
    unswitched for channel memory. At least one may be obvious if has an
    in-line fuse. Use an ohmmeter if necessary. Once you have found the
    power connections, power it from your 12 V power supply. Keep the
    volume way down and use the balance and
    fader controls to identify the speaker connections. There will be
    either 2 pairs of wires or more likely 4 pairs for front and rear
    speakers."

    If I find the power connections I can turn on the unit. The case
    will likely be a ground (this I assume to be always the case even when
    the polarity was reversed in older radios -- I digress).
    How do I trace the power pin. It may be a bit naive of me but am I
    using the ohmeter to track a resistance setting from the on/off switch?
    what if the unit is a push button does it apply different?
    Feedback will be appreciated....
     
  2. Ken Weitzel

    Ken Weitzel Guest


    Hi Netvoy...

    Wonder if you opened up the case you might not find color coded
    wires? (we all know what red is). Or perhaps, given that I'm
    struggling with a no display Chrysler unit, maybe even be lucky
    enough to find labels inside? Or silk screening?

    Perhaps visually trace the wires, if power is all you really want to
    be absolutely sure of. Going to a large choke, perhaps a crowbar,
    some good sized rectifiers, the on/off switch?

    Or if you don't mind spending a few dollars, then this might be
    helpful, particularly if it comes with good documentation.

    http://www.simplycheap.com/americaninsbk934.html

    Good luck, and take care.

    Ken
     
  3. Guest

  4. netvoy

    netvoy Guest

    Thank you for the feedback. I had checked one of the websites
    before; in fact I've used it quite a bit as this is the sixth stereo I
    am trying to wire/test this month. So far out of all six radios only
    one worked. The pin out for the Subaru unit was not in the site. The
    other two sites listed it but it shows it as a 14pin radio and the unit
    I have is a 20pin radio; must be a newer model. No luck.
     
  5. netvoy

    netvoy Guest

    I've opened quite a few not this one though. I have not seen one ever
    color coded. Although I have been able to figure out one equalizer
    this way. I have seen some labels on Toshiba TV electronic boards and
    maybe even some computers but many many times there are none and of
    limited use without experience in the particular unit. The idea of
    opening it up was put aside for I did not need another unit laying
    around in pieces while I get around to it.
    When you try to trace you come up across the cassette drive or what
    have you. I really just want to know the process before I get into the
    unit so as to minimize the chances of destruction by indiference
    (because I did not get to it for whatever reason).
    What is a crowbar?
    And yes I do mind spending, it may be wasted money if the unit does
    not work; besides it deviates you from important electronic knowledge.
     
  6. Model number would help like CQ-LF?
    Newer radios are pretty hard to find all the power connections
    correctly other than battery and then that is sometimes ACC.
    Jeff
     
  7. netvoy

    netvoy Guest

    It is a Subaru radio (printed on the left corner as you look at it); a
    Panasonic radio Model P421 printed on the radio's right hand corner.
    There are 6 additional pins must be additional auxiliary or remote
    control functions; I can only assume.
     
  8. netvoy

    netvoy Guest

    It is a Subaru radio (printed on the left corner as you look at it); a
    Panasonic radio Model P421 printed on the radio's right hand corner.
    There are 6 additional pins must be additional auxiliary or remote
    control functions; I can only assume.
     
  9. Model number will be on the top or the bottom and on rare occasions on
    the sides or back.
    The front ID number is not the model although it can be crossed to a
    model number, it is sometimes wrong.
    Even the sticker with the model number may be labeled wrong, I need two
    letters dash two letters then numbers.
    Jeff
     
  10. netvoy

    netvoy Guest

    Sorry I could not identify it as it is labeled as a reference number
    (ref no.) and garbled with a long mix of letters/numbers. If I recall
    correct it is a CQ-LF.
    On a related note. I have been looking at some diagrams on radio
    cabling and there is a pin for Illumination(+) and one for
    Illumination(-). Are these pins connected to 12v+ and GND
    respectively?
     
  11. Yes ref no is the model and yes ill + and - is power and ground but
    one may be a varried resistance if there is no seperate dimmer.
    Jeff
     
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