No power at all, dead board, like to repair it

Discussion in 'General Electronics Chat' started by tester2, Mar 11, 2010.

  1. tester2

    Thread Starter Member

    Mar 11, 2010
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    hi guys i need your help my linksys wrt54gs v4 router board look like this and this is dead no power at all, so i am trying to repaire to get power on it. please help me out how to find out burn out components on this board.

    And i am new to this board testing i don't know how to check and what spot i have to adjust the switch to test components.


    I am attaching a picture, i have to measured the voltage in the input jack and also the 3.3V after the power regulator? so where is the input jack & 3.3v after power regulator look like in the picture below.
    so how to measure this and where i have to adjust switch on meter.

    thanks

     
  2. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    See the attachment.
    1 .get a high resolution close ups of that area, I need to take closer looks. it's a must
    2 .I need two pictures of the area in the square, from both the sides of the board.
    3 .what type of DMM do you have and tell me ur electronics skill you posses
     
  3. tester2

    Thread Starter Member

    Mar 11, 2010
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    this all are my board real pictures.
    i am able to do soldering on the board, but i don't know how to check burn out components on board, so i like to know how to check components on board.
    if i track/trace a component which is burn out then i can do very well replace it, i mean i can do soldering.

    thanks.
     
    Last edited: Mar 12, 2010
  4. tester2

    Thread Starter Member

    Mar 11, 2010
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    and my multimeter look like this
     
    Last edited: Mar 12, 2010
  5. hwy101

    Active Member

    May 23, 2009
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    Do you have the original power supply that came with that router?
    It should be rated at 7.5 volts DC it's actually higher than that with no load, then it's regulated inside the unit.
     
  6. BillB3857

    Senior Member

    Feb 28, 2009
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    Am I going blind or does the 2nd set of picture show a different board than the picture in the OP.
     
  7. BMorse

    Senior Member

    Sep 26, 2009
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    Yes they are different, as he states those second set are "actual" pictures of his board....

    B. Morse
     
  8. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    See the attachment.
    One problem that you did not do what I said.
    when I zoom in I cannot get a clear view of the area I want to check, this makes things difficult.
    Now the below things are assumptions made by the low res of the pick as I cannot be sure of what I am seeing.

    But this might help.
    see the area in the red lines, this the area I need to concentrate on for now.
    see the label fuse. I want you to check for zero resistance of that component for now and post back. don't try to take it out yet, in fact don't do any think except measure the resistance.
    If possible try to get closeup pictures with better lighting.
     
  9. tester2

    Thread Starter Member

    Mar 11, 2010
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    in post #1 is not my board picture.

    but in post #3 is my real wrt54gs v4 Linksys Router board pictures.

    i tried many diffrent power suplies from 7v to 12v none work at all.
     
  10. retched

    AAC Fanatic!

    Dec 5, 2009
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    Uh oh. Which one did you start with? The 12v may have applied upwards of 15v hopefully not frying anything else.. I believe you should be using a 5.

    By the way, did you check the wall outlet to see if there is power there?

    I had a friend who swore up and down his TV was broke.. Had it in pieces when I got there. It was starting to get dark so I grabbed a lamp to bring over, plugged it in and guess what? The TV was fine. The GFCI tripped.
     
  11. tester2

    Thread Starter Member

    Mar 11, 2010
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    on the yellow 2 legs component written this [P 30V, NR 3H] just now i take few clear pictures of this spot.

    and i put switch on meter at 20k then i touch black & red wires to yellow component either way exchange wires shows 0.00 only on yellow component.
     
  12. retched

    AAC Fanatic!

    Dec 5, 2009
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    30 volt 3Henry inductor?

    You have 0volts from pin to pin? See if you have continuity..
     
  13. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    Next step it to check power.
    Plug in the original adapter, power it up.
    Put the DMM in DC Voltage mode.
    In the picture, I have labeled ground, this is you negative point, connect the black meter probe and keep it connected throughout the measurement
    Next use the red probe to measure the voltage at the points I have labeled 1 via 8.
    Note them and post back.
    Be sure that power is available at the adapter output
     
  14. retched

    AAC Fanatic!

    Dec 5, 2009
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    So no voltage through the inductor? or is it a fuse? Rifaa, any idea?
     
  15. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    Not sure..hard to tell.
    I am assuming it's a fuse link
     
  16. tester2

    Thread Starter Member

    Mar 11, 2010
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    what is DMM & how to put in DC mode. And i like to know if i connect adapter & power ON in this situation can i check the spotes with meter when power is ON.
     
  17. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    We need to check voltage..put the meter in the range to which you measure dc voltage.
    You have to power the board using the adapter. then only you can get the voltage

    DMM.. digital multi meter.
    Put it in DCV 20 and do the testing
     
  18. tester2

    Thread Starter Member

    Mar 11, 2010
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    meter put on 20 DCV & Black wire connect to Ground with out moving then Red wire moving fron spot 1 to 8 the below are the readings here

    Spot 1- 0.00 , 2-0.00 , 3-0.00 4-15.50 , 5-15.45 , 6-15.50 , 7-15.48 , 8-15.46
     
  19. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    That's good. now give me no. 9
     
  20. tester2

    Thread Starter Member

    Mar 11, 2010
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    I put meter on 20 DCV & Black wire connect to Ground then Red wire on spot 9 the below is readings


    spot 9-15.29 shows
     
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