Voltmeter Dip Switch Configuration Mystery

Discussion in 'The Projects Forum' started by Justinwat, Dec 5, 2009.

  1. Justinwat

    Thread Starter Member

    Dec 15, 2008
    17
    0
    I have this panel voltmeter to measure a small 12vdc stereo I made. I don't have instructions with it but I found photos on Virtual Village's website. I can get it to read out 0.00 when I hook it to a 9v power supply but then when I attempt to read a 12vdc battery the leads start to heat up. The read out does change but does not measure the voltage. I'm surprised it still lights up at all since it's been heated up during a few attempts now. I'm trying to figure out the correct dip switch configuration before I fry it to death. I'm assuming the dip switch is used to adjust the voltage range it measures and is the key to my problem.

    Does anyone have this meter and/or know the dip switch config to make it work to measure a 12vdc source?

    I've tried 1:On / 2-5:Off and 1&5:On / 2-4:Off

    Thank you!
     
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  2. CDRIVE

    Senior Member

    Jul 1, 2008
    2,223
    99
    Which pair of wires are getting hot, the power supply pair or the source that you're measuring?

    I fear that if either got hot enough for you to feel you've already fried it.

    Please post the link where you found these images.
     
  3. BMorse

    Senior Member

    Sep 26, 2009
    2,675
    234
    can you post more info on the meter? maybe a Model # and Manufacturer? from what you have shown, it does not do any good, since I can not tell what the functions of the dip switches are....

    And CDRIVE: the power input state 5 to 15 volts, not just 5, so 9 volts would be ok.
     
  4. CDRIVE

    Senior Member

    Jul 1, 2008
    2,223
    99
    I realized that immediately after I posted that statement. I saw that no one had replied yet, so I edited it. You must have made this reply during that brief period. ;)
     
  5. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
  6. Justinwat

    Thread Starter Member

    Dec 15, 2008
    17
    0
    It was the test source wires that were connected to 12vdc that became warm.

    Photos found: http://www.virtualvillage.com/20v-blue-lcd-digital-meter-for-system-monitoring-001490-021.html

    The only information on the meter itself is: UP-8135A (printed on the board.)

    This is all the info I have. I know it's a long shot but if anyone can help me figure it out it is you guys on this site. Thanks again.

    Beenthere: I too ran across that data sheet but unfortunately I don't think it's for the meter I have.
     
  7. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    The reason I suggested tracing the switch traces is that they may do no more than set the position of the visible decimal point.
     
  8. CDRIVE

    Senior Member

    Jul 1, 2008
    2,223
    99
    The information found in this link seems to indicate that the dip switch sets two parameters, Voltage Range (0 to 1.999V) and (0 to 19.99V). The other parameter is Resolution (1mV or 10mV). I can't imagine either one of these settings being responsible for wire getting hot. I mean, for wire to get hot enough to notice you have to be pulling significant current!
     
  9. CDRIVE

    Senior Member

    Jul 1, 2008
    2,223
    99
    Since you don't have instructions for this DVM can I assume that you didn't purchase from the source in your link? If not, where did you get it and how do you know that it's not defective?

    What's really odd about your issue is that even if the meter is defective it would seem nearly impossible for the input leads to draw excessive current at the Vx input. I can't imagine an input that wouldn't present a high resistance voltage divider circuit. Even if you had the dip switch set to 1.999V while measuring 12V, pulling so much current as to heat the wires...??..!!:eek:

    Are you sure that your model is not an Ammeter?
     
  10. Qumefox

    New Member

    Dec 22, 2009
    1
    0
    I bought a small pile of these meters too. I figure the original poster got it solved since there hasn't been any more questions, but after having to figure this out for myself, here's how the thing is wired.

    UP8135A / UP-8135A 2v/20V DC digital panel meter wiring

    On the power input jack.

    Pin 1 Measurement - (closest to the DIP switches, blue wire on the meters I have)
    Pin 2 Measurement + (Green wire. Don't get these polarity reversed. They get hot if you do, at least when driven by the same source as the supply)

    Pin 3 Supply - (Black wire)
    Pin 4 Supply + (Red wire 5v - 15v)

    Dip switch function
    1 - First decimal
    2 - Second decimal
    3 - Third decimal
    4 - Unused (as far as I can tell)
    5 - Range select (On - 20V, Off - 2V)

    So the switch settings for 2v are
    1 - on
    2 - off
    3 - off
    4 - off
    5 - off

    and 20v is
    1 - off
    2 - off
    3 - on
    4 - off
    5 - on

    One other thing i'll note with these meters. When set to 20V, the meter will zero itself with an open connection. On the 2V setting, the reading will float near the last measured voltage until connected to something else or the leads are shorted.
     
    Last edited: Dec 22, 2009
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