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Help identifying components

Discussion in 'General Electronics Discussion' started by charnich, Mar 30, 2013.

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  1. charnich

    charnich

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    Mar 17, 2013
    Hi,
    I'm trying to recreate an arcnet circuit. I'm new to circuits but have a fair amount of tinkering experience. I will have a clean board with the circut pre-fabbed but needs the components. I have found the major components online but its the smaller ones I need help with. Specifically, the small ones labelled .1uf with the gold stripe in the middle, 20pF with the brown stripe in the middle, the 2 yellow blocks that read "106V Uo5JT" (the boards next to these is labeled c106), and the metallic cylinder (possibly a crystal), it is labeled "200 ESCP". I'm attaching some photos

    If anyone can tell me what these different components are called (i.e. resistors capacitors, crystals etc) it would help me look up the correct parts.

    Thank you!
     

    Attached Files:

  2. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    Jan 21, 2010
    It would probably be easier to start from the electrical specification and build something from scratch.
     
  3. charnich

    charnich

    9
    0
    Mar 17, 2013
    Hi Steve,
    You may be right but I don't have that option. This is a proprietary board for a eyeglass frame tracer. They make both arcnet and arcnet ready models. I have one of each and I need to have arcnet for each one. So I have both boards which are identical except for the arcnet hardware. The specs aren't available and a new arcnet board is several thousand dollars so the only chance I have is to copy the arcent boards. I've already figured out the bigger components and I'm hoping someone out the with some experience with different components can get me on the right track.

    I've attached a pic of each board.


     

    Attached Files:

  4. davenn

    davenn Moderator

    13,596
    1,875
    Sep 5, 2009
    They are just standard components

    .1uf = 0.1uF capacitor
    20pF = 20pF capacitor
    106V = 10uF capacitor
    metallic cylinder yes a crystal, for the oscillator for the micro chip
    200 on it ? who knows, could be 2.0 kHz, 20kHz, 200kHz, 2MHz ??? knowing that chip and get its datasheet will tell you what crystal it needs

    Dave
     
  5. BlinkingLeds

    BlinkingLeds

    180
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    Feb 23, 2013
    What about powering the crystal and measuring it's frequency?
     
  6. davenn

    davenn Moderator

    13,596
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    Sep 5, 2009
    well either the existing circuit its in can be powered and a freq measurement taken
    or if that cant be done then it would need to be unsoldered and installed into a different oscillator circuit for measurements

    Dave
     
  7. Rleo6965

    Rleo6965

    585
    9
    Jan 22, 2012
    Do you have idea what kind of board was arcnet you want to recreate? I have experienced with arcnet network card before and that very old network topology.
     
  8. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    I think I discarded the last of my arcnet cards more than 10 years ago. I used to run Lantastic on them.

    I'm sure there were some hybrid modules on them that may be difficult to reproduce.
     
  9. charnich

    charnich

    9
    0
    Mar 17, 2013
    You're right, it is very old. The good news is that they still produce the arcnet components. I've located those on Mouser. Unfortunately, my lens edger can only communicate with an arcnet frame tracer. It is about 15 years old. New edgers are 30-50k so I'm pretty much stuck with what I have.

     
  10. charnich

    charnich

    9
    0
    Mar 17, 2013
    HI, thank you for the reply.

    It appears form the printing on the board that the frequency is 20 MHZ.

     
  11. charnich

    charnich

    9
    0
    Mar 17, 2013
    Hi Dave,
    Thank you for the reply. I'm looking up the different caps and I need to select a voltage. Obviously I will match the capacitance. The power supply states that the max output is 65 W. There are 5 output pins. here is what they say:
    Pin 5 +5V 6A
    Pin 4 +12V 3A
    Pin 2 -12V 0.8A
    Pin1 N/C
    Pin3 Common

    All voltages appear to be DC, but I don't understand why pin 2 is (-) Can I assume DC caps will work sine the power supply is converting to DC?

    What voltage caps should I be looking for. Can I just go as high as possible to be safe. In other words is there any risk to choosing excessively high voltage. I was thinking something in the 250 V range to be safe. What do you think?


     
  12. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,396
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    Jan 21, 2010
    Pin 2 is a negative voltage with respect to ground (common).

    The voltage rating of capacitors depends on where they are located in the circuit.

    In general, for lower value capacitors (less then 1uF), you could probably safely choose 50V (or higher) rated capacitors.

    For higher value capacitors (100uF and up) you probably need to select an "appropriate" voltage. This would be about 1.5 times the voltage applied or higher. This might mean from 7.5V to 36V, depending on how they're connected wrt the power supply. Note that there are standard voltage ratings (and 7.5 & 36V are not examples of them) so you pick the next highest voltage rating. 6.3V, 10V, 16V, 25V, 50V, 63V 100V are all fairly commonly seen voltage ratings.

    For capacitors between 1uF and 100uF, you follow whichever of these rules seems reasonable.

    Note that the advice given here (primarily the 50V rating for low value capacitors) would differ for different environments, depending on the supply voltages, and what things are interfaced to.

    Beware that the board may have a few comparatively high voltage capacitors and other components that are connected to the BNC socket since these cards were designed not to be damaged in the case of voltage spikes etc being imposed on the signal.
     
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