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Help Identifying Component

Discussion in 'Troubleshooting and Repair' started by scupbucket, Oct 27, 2014.

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  1. scupbucket

    scupbucket

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    Oct 27, 2014
    Hi guys… First time post! I was hoping someone might point me in the right direction. I’m a total newbie with electronic components and I’m currently working on an old folding style SLR Polaroid camera whose metering system is no longer functioning properly. I do a lot of work on these but am trying to familiarize myself with the electronics involved without having to use donor electronic control modules. Exposure is determined by a photodiode which triggers a series events that produce a finished photo. Unfortunately I’m getting no response when the camera tries to meter ambient light levels and shots become overexposed to the point of being useless. I’ve seen older models utilize a resistor/capacitor combo which I believe is part of the metering system but on this particular model, I have no idea what the component is next to the resistor. Inductor maybe? If so I can’t find any information that describes a single band inductor. Is it possible these components have aged to the point of being defective? Any help would be appreciated!


    Matt
     

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  2. davenn

    davenn Moderator

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    Sep 5, 2009
    hi there
    welcome to the forums :)

    it mite be a zero ohm resistor ( only a remote possibility for an inductor or capacitor)
    I suggest you lift one end and do a resistance test

    Dave

    EDIT .... is it directly in parallel with the resistor ... that is, is its pins going to the same circuit track pads as the 2 pins of the resistor ? If so, then a capacitor would be a high probability
     
  3. Arouse1973

    Arouse1973 Adam

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    Dec 18, 2013
    Hi Matt
    Could it be a resistor using the old RMA colour scheme where the body colour is part of the value?
    Adam
     
  4. scupbucket

    scupbucket

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    Oct 27, 2014
    Thanks for the Replies!


    Dave – Yes, the mystery component shares tracks that lead to an IC chip below the photodiode. I’ll provide more images this evening. Could this just be an older style cap? I measured with my VOM and got no reading whatsoever.
     
  5. davenn

    davenn Moderator

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    Sep 5, 2009
    please show a pic of the other side of the PCB in at area :)
     
  6. scupbucket

    scupbucket

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    Oct 27, 2014
    OK... I took a few more shots of the rear of the board for the mystery component. I'm also including an earlier design that clearly shows a capacitor being used. It's important to note that the later model ECM is used for cameras that use a higher speed film, in this case 600 ISO. The earlier design is for cameras that shoot with 200 ISO (if that helps at all). The top image shows red dots where the resistor passes through the board and blue where the mystery component rests. The magenta dot indicates where a capacitor, like on earlier models, would have been placed. Sorry it's difficult to see the top image. It seems the ECM manufacturer or Polaroid epoxy dipped the boards to avoid lengthy repairs by techs back in the day. If failure analysis concluded that the substrate was defective or causing another part of the camera's functions to fail, they would simply replace it with a new one. One day I would like to find that unopened stash of ECMs... :)
     

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  7. davenn

    davenn Moderator

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    Sep 5, 2009
    the last photo in that set appears to be of a different board

    different resistor and what appears to be a mylar capacitor not that thing with the blue band

    what's the story ?

    Dave
     
  8. scupbucket

    scupbucket

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    Oct 27, 2014
    Yes... the last two photos are of an earlier design that I thought might help illustrate the similarities of the component layout. Instead of the blue band component a capacitor was used on earlier models.
     
  9. davenn

    davenn Moderator

    13,877
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    Sep 5, 2009
    OK

    do you have a capacitance meter ?
    maybe your multimeter has that function ? if so life one end of the blue banded component and see if it has a reading

    D
     
  10. KrisBlueNZ

    KrisBlueNZ Sadly passed away in 2015

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    Nov 28, 2011
    How did you measure it? You need to set your meter to resistance range - if it has several, choose the lowest one, usually the 200Ω range - and connect the probes across the component.

    The meter will then tell you the resistance. If it's a digital meter, it can give you several indications:
    • An "overload" indication often looks something like "0L" on the display. This means that the part is open-circuit. To see what your meter's overload indication looks like, select a resistance range and don't touch the probes on anything.
    • A short circuit is indicated by a small number, often less than 1.0, on the display. To see what your meter's short circuit indication looks like, select a resistance range and hold the probes together.
    • Some other indication is telling you the resistance of the part. If you've selected the 200Ω range, this number will be in ohms (Ω). If your meter is auto-ranging, the display will show either Ω, kΩ, or MΩ, meaning ohms, kilohms (1000 ohms) or megohms (1,000,000 ohms).
    You need to desolder and lift one end of the component before you measure it, otherwise other components in the circuit may affect your reading.
     
  11. scupbucket

    scupbucket

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    Oct 27, 2014
    Ok gents... back again. Thanks for all the suggestions. Thanks for the tips KrisB. I tested for resistance in all ranges and again no reading. Dave, I don't have a cap meter but it might be worth the investment. So is it safe to say I can rule out resistor?

    I had some time over the weekend to strip down a few other cameras I had of the same model and found these in the exact same location instead of the single band mystery component. Same size and green body color but 5 bands? Thanks for all the help!
     

    Attached Files:

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