1. Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.
    Dismiss Notice

Plasma cut 50

Discussion in 'Repairing Electronics' started by agguilar, Aug 3, 2018.

Tags:
  1. agguilar

    agguilar New Member

    Joined:
    Aug 3, 2018
    Messages:
    22
    Likes:
    0
    I use this video I don't have a powe supply to test but I use a phone charger that haves 9v output 350mA
    In the pictures I'm showing the reading I get from the power adapter that is 13.50 and in the other picture is the reading touching the zener diode


    To measure the zener diode and I'm getting a reading of 0.10 on the multimeter don't know if I'm doing it the right way please any help will be great, thanks !
     

    Attached Files:

  2. agguilar

    agguilar New Member

    Joined:
    Aug 3, 2018
    Messages:
    22
    Likes:
    0
  3. agguilar

    agguilar New Member

    Joined:
    Aug 3, 2018
    Messages:
    22
    Likes:
    0
    i dint find it serch all ove the web but i found this part number or name dont know how to serch for this type of electronics,
    SOD 80C LL34 MINI MELF
    (MiniMelf (MMA) Size 0204: length: 3.6 mm, diam.: :1.4 mm. Typical rating for resistors = 0.25 to 0.4 watt / 200 V)
    this have similar characteristics , will this work to replace the one im looking for ??? thanks !
     

    Attached Files:

  4. dave miyares

    Dave New Member

    Joined:
    Jan 12, 1997
    Messages:
    2
    Likes:
    -10
  5. KeepItSimpleStupid

    KeepItSimpleStupid Well-Known Member Most Helpful Member

    Joined:
    Oct 30, 2010
    Messages:
    10,200
    Likes:
    1,129
  6. agguilar

    agguilar New Member

    Joined:
    Aug 3, 2018
    Messages:
    22
    Likes:
    0
    :banghead:I just notice something :banghead:when measuring:banghead: that is not the part I need This is the picture of the parts from the 2 ones that was not burn so sorry for not looking carfuly
     

    Attached Files:

  7. agguilar

    agguilar New Member

    Joined:
    Aug 3, 2018
    Messages:
    22
    Likes:
    0
    Ok wait I'm stupid, I think I remove the black strip will trying to remove the glue, I just don't know what the hell im doing
     
  8. dave miyares

    Dave New Member

    Joined:
    Jan 12, 1997
    Messages:
    2
    Likes:
    -10
  9. agguilar

    agguilar New Member

    Joined:
    Aug 3, 2018
    Messages:
    22
    Likes:
    0

    Attached Files:

  10. KeepItSimpleStupid

    KeepItSimpleStupid Well-Known Member Most Helpful Member

    Joined:
    Oct 30, 2010
    Messages:
    10,200
    Likes:
    1,129
    The circuit you have is very like;y to have similar bits nearby and for the Blank thing a resistor because of it's designation of R. A resistor marked 101 is 100 ohms. A "10" and 1 zero. so 221 is 220 ohms, 103 is 10K. Wattage you have to get by size,

    When you measure "in-circuit", the parts around the part your measuring interact, so when using the diode test and you get 000 and 000 in both directions, you need to know if it's a surrounding part.

    You may have to "reverse engineer". make a schematic from the PCB to enable better gueses.

    Zener diodes, the ones with the (based in your pdf) colored band will likeley act like regular diodes unless they are something like 2.1V.

    Your meter in the diode range may measure in mV rather than volts, so 686 is 0.686.

    I have a $7.00 meter I got free that does this.

    The value of a resistor that you can;t read, you may be able to make out parts of them and there may be a similar bit elesewhere on the board.

    if you happen to find a bad zener diode that test bad in and out of circuit, your going to have to find a voltage source and a resistor to say limit the current to 1-10 mA and measure the voltage across it. For a 5.1 V zener diode, you;ll have ~0.6 one way and 5.1 the other.

    A 9V battery and two 9V batteries in series would be a place to start.

    Don;t forget to take photos before and after to check polarity.

    For the dimensions, I have a dial caliper, so i blew up your jpg with the ruler. Measured the ruler for 1 cm for my screen in mm. Now i have a conversion to apply for other components measured on the screen.


    So, if I wanted to measure the black resistor, I could measure the screen value of the diode and I know the real dimensions, so i can calibrate that way.
     
  11. agguilar

    agguilar New Member

    Joined:
    Aug 3, 2018
    Messages:
    22
    Likes:
    0
    Thanks that, will try and do all that, when you say "made a schematic of the pub board " is it something like the picture
     

    Attached Files:

  12. KeepItSimpleStupid

    KeepItSimpleStupid Well-Known Member Most Helpful Member

    Joined:
    Oct 30, 2010
    Messages:
    10,200
    Likes:
    1,129
  13. agguilar

    agguilar New Member

    Joined:
    Aug 3, 2018
    Messages:
    22
    Likes:
    0
    Ok before I star drawing the schematic I was looking to know the name of the particular part and I found a lot of similar ones in one of the pictures you can actually see the value of the parts Can I use one of this parts for replacement ? Mine is a plasma cut50 and not a welder, that I think this board at made for , again thanks for all the help!
     

    Attached Files:

    Last edited: Aug 11, 2018 at 12:08 AM
  14. agguilar

    agguilar New Member

    Joined:
    Aug 3, 2018
    Messages:
    22
    Likes:
    0
    Don't know if this will work
     
  15. agguilar

    agguilar New Member

    Joined:
    Aug 3, 2018
    Messages:
    22
    Likes:
    0
  16. KeepItSimpleStupid

    KeepItSimpleStupid Well-Known Member Most Helpful Member

    Joined:
    Oct 30, 2010
    Messages:
    10,200
    Likes:
    1,129
    Not sure what your looking for now.

    I found this: https://aip.scitation.org/doi/pdf/10.1063/1.5002041

    It's a schematic for a plasma driver and it's not an H-bridge. A reverse-engineered schematic (which are a pain to do) will help figure out the function of the diodes.
     

Share This Page

  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.
    Dismiss Notice