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Digital Multimeter Problem "-1" !!!

Discussion in 'Troubleshooting and Repair' started by battery.13v, Dec 21, 2015.

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  1. battery.13v

    battery.13v

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    Dec 21, 2015
    Hello everyone, i have a Digital Multimeter DT9250, so yesterday I was firing a fire with a lighter (Electric Lighter), and i was concerned about the electricity in produce to make the spark :oops: .... So I disassembled it, I bring my digital multimeter, I put it in the highest DC voltage and I test it .... However it suddenly rises to infenity and drops to -1, and stuck in -1 one in all the options (Amperage, Resistance, DC AC voltage, Frequencies, Capacitance), and the continuity test is the only one who is working now .... Please Help me, I worked for 2 weeks to buy this Multimeter and I don't wan't to throw it to the junk .... :(
     
    Last edited by a moderator: Dec 21, 2015
  2. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    Jan 21, 2010
    yeah you've probably fried it.

    It might be worth removing the batteries tho see if that resets the meter but I wouldn't hold a lot of hope.
     
  3. Tha fios agaibh

    Tha fios agaibh

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    Aug 11, 2014
    :rolleyes:I know someone who can sell you a slightly used meter...
     
    Martaine2005 likes this.
  4. battery.13v

    battery.13v

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    Dec 21, 2015
    My digital multimeter is rated to 1000V DC, but we all know that when we exceed the amperage a Fuse blow up and you just have to change it , However in the Voltage testing we don't know what is the first component that will fail if Voltage Exceed the limit, so if someone know, please tell me ....
     
  5. hevans1944

    hevans1944 Hop - AC8NS

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    Expensive lesson in high-voltage piezo-electric spark generation. The User's Manual clearly states: "Never use the meter to measure voltage that might exceed the maximum allowable input value of any function." Good advice for any measuring instrument.
     
  6. Martaine2005

    Martaine2005

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    May 12, 2015
    I am not sure of your fault finding experience,
    Most DMMs have very similar protection circuits. (according to Dave Jones)
    This video might be very helpful.. Jump to 15:50 if you are not interested in the Amps side.

     
    Last edited: Dec 21, 2015
    dorke likes this.
  7. dorke

    dorke

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    Jun 20, 2015
    You probably mean DT-9205 (not 50).
    These are low end cheap chineese DMMs selling for under 10$.
    What do you mean by " I worked for 2 weeks to buy this Multimeter" ???

    Sorry to say but most likely your DMM is a gonner...:(
    One Needs to think before one does somthing ...
     
    Last edited: Dec 22, 2015
  8. Tha fios agaibh

    Tha fios agaibh

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    Aug 11, 2014
    No way would I trust that meter for anything near 1000v. Even if the meter itself is ok, your putting your life in the hands of those HongKong test leads.
     
    Martaine2005 likes this.
  9. Gryd3

    Gryd3

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    Jun 25, 2014
    I second that...
    But would personally risk it with a piezo element used in a starter...

    In any case. Take a look here : https://en.wikipedia.org/wiki/Dielectric_strength
    For an electric starter to work, it needs a spark. The spark needs to travel through air... so, if you know the distance, you can figure out the minimum voltage that may be required for the spark.

    We can also work backwards if we know the voltage, we can determine how far a spark can jump.

    The page I linked shows Air at 3Mv/Meter ... That's 3 Million Volts per meter, or 3000V per mm.
    If your meter is rated at 1000V, then anything that can make a spark over 1/3rd of a millimeter will damage it.

    Remember that a spark jumps through air... there is nothing stopping it from jumping across parts or traces within a device... This is why static discharge can be so nasty. Your voltage spike from the starter could have directly damaged a component in it's path... or jumped to another component and damage that.
    I'm willing to bet your meter is toast.

    Expensive lesson learned.
     
    Tha fios agaibh likes this.
  10. davenn

    davenn Moderator

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    Sep 5, 2009
    I thought that would be pretty obvious ;) ;)

    he worked for 2 weeks to save the money to buy the meter
    Not everyone in the world has lots of income and specially if still a student


    D
     
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  11. battery.13v

    battery.13v

    6
    0
    Dec 21, 2015
    2 Weeks not just for the Multimeter ... however the multimeter consist of 50% of my electronic buys ... i am a begineer in electronic field so it's a good lesson ... it's worth it .... Thx for all of you for your help ... and i will see the Videos and see if i could repair it without a multimeter,o_O however i have to buy one in anyway ....
     
  12. Colin Mitchell

    Colin Mitchell

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    You cannot repair it.
    The high voltage has damaged FET 206 on the board along with IC 103.
    These cannot be obtained.
     
  13. Tha fios agaibh

    Tha fios agaibh

    2,115
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    Aug 11, 2014
    Screenshot_2015-12-22-01-02-43-1.png Impressive how exact you are Colin.
     
  14. Gryd3

    Gryd3

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    Normally I'd laugh my *** off, but the OP did share his model#, and it's possible that Colin has the same model#, or a circuit diagram for it.
    I would be interested in verifying this though... perhaps there is indeed a couple of replaceable parts the OP can swap out to make this meter work again?
     
    Martaine2005 likes this.
  15. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,449
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    Jan 21, 2010
    The problem is that Colin's post history is more suggestive of this being snark.
     
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