Help with identifying a part

Discussion in 'General Electronics Chat' started by wehtiko, Jun 17, 2015.

  1. wehtiko

    Thread Starter New Member

    Jun 16, 2015
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    I'm having a hard time identifying one of the diodes on a board I'm trying to repair. The stamping on the part looks like a Motorola logo. The closest guess I've got so far is a SMD version of a 1N747 but can't find any documentation to back it up. I've asked help from a rep at Digikey and came to the same conclusion but also can't find anything to back it up. I have attached a picture of it, it's the D1 diode.

    CM150616-19214102.jpg

    If anyone can help, that will be greatly appreciated!
     
  2. Kermit2

    AAC Fanatic!

    Feb 5, 2010
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  3. Hypatia's Protege

    Distinguished Member

    Mar 1, 2015
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    Off hand I'd say what you have there is a 1 Ohm resistor:)

    Failing that please check the resource linked by @Kermit2 or here: http://www.s-manuals.com/smd

    EDIT: Sorry, was looking at the wrong part:oops:... One moment please...

    Best regards
    HP
     
    Last edited: Jun 17, 2015
  4. wehtiko

    Thread Starter New Member

    Jun 16, 2015
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    Yes, I did take a look at the code book yesterday. If I look up codes beginning with 74 and they all point to transistors except for one that points to a schottky diode but that part comes in either a SOT-23 or a SOT-143 package and this one is SMA.
     
  5. Hypatia's Protege

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    Indeed:( My searches (for 'm747', 'lm747' and '747') on Electroschematics (Code-Book), Manuals.com and 'Dear Old' Google produced less than helpful results -- (Meaning the device is likely of propitiatory manufacture and/or bears an 'in-house' ID stamp) --- While I concur with the consensus that it is likely an SMD-packaged 1n747, one hesitates to 'endorse' said opinion sans cognizance of the 'stakes' involved...

    Apologies that I wasn't of much assistance:oops:

    Best regards and good luck!
    HP:)
     
    Last edited: Jun 17, 2015
  6. nerdegutta

    Moderator

    Dec 15, 2009
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    Is it possible to resonate forward to the component?

    What does the PCB do?
    Any chance of getting the schematic?
    Any other numbers to search for?
     
  7. wehtiko

    Thread Starter New Member

    Jun 16, 2015
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    Hey, I really appreciate the effort to help me with this. Thanks!
     
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  8. wehtiko

    Thread Starter New Member

    Jun 16, 2015
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    This is a proprietary circuit that integrates with our device to open locks. Unfortunately all documentation were not part of the trade when we've bought the company and our customer wants us to at least repair the devices when they fail. We don't even know how our device communicates with the circuits because this was a special firmware and was not part of the trade either.
     
  9. Hypatia's Protege

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    Assuming the part is indeed propitiatory, Motorola, upon (even casual) request will advise you as to the owner of the 'specification' -- In my experience such 'owners' are often quite cooperative!:)

    Again, best of luck!:)
    HP
     
  10. wehtiko

    Thread Starter New Member

    Jun 16, 2015
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    I'll try that avenue and see where it leads me. If I find anything, I'll post it here. Thanks again!
     
  11. ian field

    Distinguished Member

    Oct 27, 2012
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    Do you have a working board you can borrow a "D1" for testing?

    The diode check function on a DMM will give you a fair idea what type from the Vf, physical size is a reasonable guide to current rating.

    The voltage rating could take more detective rating - if its a Shottky-barrier; the voltage rating probably isn't more than 60V.
     
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  12. wehtiko

    Thread Starter New Member

    Jun 16, 2015
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    Unfortunately I don't have one to test with.

    Doing other tests lead me to believe that the problem might be lying elsewhere and maybe not in the diode
     
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