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Opinion for an ESR meter before the garbage can!

Discussion in 'General Electronics Chat' started by whiz115, Jan 1, 2018.

  1. whiz115

    whiz115 Member

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    Hi! happy new year with lots of successful electronic projects for all! :)

    In the attached pictures you can see the schematic and the pcb for an esr meter i've built few years ago
    this thing....never worked as it should, it seems functional but the capacitance measurement always
    shows CX ----

    i tried alot to troubleshoot it....measured every component for broken joints changed most of the ICs
    in case of a faulty one but still it can't perform any measurement.

    i've spent alot of time and effort to build this device also the component cost wasn't exactly negligible
    so now it ended up one step before i salvage it and throw it to the garbage can. :/

    would you like to help me save it?

    P.S original project was descussed in the following Russian site
    http://pro-radio.ru/measure/3288/

    ESR2.png

    ESR3A.png
    ESR1.png
    ESR4A.png
     
  2. hyedenny

    hyedenny Member

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    I see a lot of potential solder-bridges, and the board is a bizarre layout.
    Did you check with a scope to see if the timer section is working?
     
  3. KevinW

    KevinW Member

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  4. dave

    Dave New Member

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  5. whiz115

    whiz115 Member

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    checked once again for broken joints or bridges and seems fine.

    currently i dont have a scope, only a frequency meter @10MHz is available
    can you point where i should measure and what? thank you.

    The pdf is so great and looks like it offers full support for somebody who wants to build
    the instrument it describes.. but how exactly it can help me?
     
    Last edited: Jan 4, 2018
  6. schmitt trigger

    schmitt trigger Active Member

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    A PCB layout that simultaneously uses SMT components, no solder mask, and is intended for assembly by hobbyists, is a recipe for disaster.

    I would check for solder bridges at every SMT component using a microscope. Usually, microscopic solder whiskers or remaining flux can cause enough leakage to cause circuit problems.
     
  7. whiz115

    whiz115 Member

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    ok i will check again and i'll let you know.
     
  8. whiz115

    whiz115 Member

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    There's a missing 100nF capacitor which i think it's not important,because
    in the Russian site i've noticed some others they also skipped that cap, it's
    underneath the micro controller next to the 22pF caps for the crystal.

    other than that i can't find any problem in the smd side, since the device
    turns on, how can we isolate the problem?

    i'm uploading the pcb layout.

    . PCB_LAYOUT.png
     
    Last edited: Jan 4, 2018
  9. whiz115

    whiz115 Member

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    Would you like to help me with that?
     
  10. whiz115

    whiz115 Member

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    guys nobody? is it that hard?...
     
  11. schmitt trigger

    schmitt trigger Active Member

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    I'm really sorry but.....
    It is because you don't have the proper test equipment. A frequency meter is useless here.

    And troubleshooting from a distance via a forum, it makes it even harder.

    And without the ability to read Russian, it makes it impossible.
     
  12. whiz115

    whiz115 Member

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    it's quite hard for me to find an oscilloscope this period, are you sure it's the only way so i can fix
    the esr meter?

    this is not serious obstacle, i've done it before, help others and also helped by others
    to troubleshoot electronics. (only once years ago and only on this forum i had to send a
    pcb to ericgibbs so he can see it from near and fix it). THANKS again ericgibbs!! :D
    isn't he moderator anymore?? :S

    also this one is not so much problem...i can't read Russian too, but
    with google translator i could understand alot from that website.
     
  13. debe

    debe Active Member

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  14. whiz115

    whiz115 Member

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  15. debe

    debe Active Member

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    Un fortunately with electronics ive found theres so mutch progress that some times, its time to move on to something more modern & versatile.
     
  16. whiz115

    whiz115 Member

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    what do you mean "more modern" ? this is not a cell phone or a PC so i can upgrade.
    it's a DIY instrument :)

    rethinking what you told me, i don't understand why you find a scope so mandatory!
    the waveform should be a square wave or something similar to that, what is
    important it's if there is any oscillation...(since from what i know) these instruments
    pass an ~100KHz to the capacitor under test, am i wrong on that?

    the PIC microcontroller starts so i guess i don't need to measure if there's a 20MHz oscillation.

    the ~100KHz test frequency should come out from the op-amp..right? if yes, where do i take
    that measurement??

    guys pls a little bit help i need.
     

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