How to identify faulty IC in the card

Discussion in 'The Projects Forum' started by rakesh1963, Sep 28, 2012.

  1. rakesh1963

    Thread Starter New Member

    Sep 27, 2012
    2
    0
    How to identify faulty IC in the card

    I have a DC servodrive Card and Servomotor connected with it. The drive card is in the panel and the motor is connected to the machines.

    I am having a problem with the drivecard which has 100's of SMD IC and 1000's other discrete component like transitor, FET, SCR, Mosfet, diode .

    All the connecting power connections to the drive is done with the socked which is fixed with panel. So that I can powerup the card only by inserting the card in the panel.

    I want to check the drive card outside the panel.

    The problem with the card is the motor is jerking. i.e vibration in its position with forward and reverse torque.

    How do I check for 100% faulty IC and other discrete component without removing from the board with minimum of testing instruement.
     
  2. MrChips

    Moderator

    Oct 2, 2009
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    Without a circuit schematic and experience trouble-shooting complex electronic circuits it would be a difficult task. The board is almost condemned to the dump.
     
  3. John P

    AAC Fanatic!

    Oct 14, 2008
    1,634
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    If the system is capable of doing what it's designed for--even if it's not doing it right--then I wouldn't suspect a failure. What I'd look for would be some adjustment setting that's wrong. Can you do anything at all that changes the behavior of this device? It would be a bad sign if there's absolutely no response to the controls.
     
  4. rakesh1963

    Thread Starter New Member

    Sep 27, 2012
    2
    0
    All the adjustments settings are done as per the instruction on the drive. Still the problem remains the same.

    My question is what are the ways of testing(checking) IC when they are on the card without removing it from the card. Schematics or circuit drawing will not be available for the drive card as it happens with all the card because manufacturer does not provide detail circuit drawing.
    Can you please help....
     
  5. wayneh

    Expert

    Sep 9, 2010
    12,123
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    What you are asking for is effectively impossible, IMHO. Time would be better spent ruling out mechanical issues. By that I mean circuit traces, cracked circuit board, bad solder joints, loose connectors, dirty potentiometer wipers, etc. Anything that might cause intermittent connections. Maybe you can confirm that the motor operates properly, to rule it out? How's the power supply?

    With a detailed schematic, showing meter probe points with voltages and waveforms, you might have a chance. Without all that, a replacement board is a better investment than trying to reverse engineer such a complicated beast.
     
  6. THE_RB

    AAC Fanatic!

    Feb 11, 2008
    5,435
    1,305
    It could be a sensor issue.

    Really you should have the service manual for the whole machine, which will have test procedures you carry out step by step. You may also need a test adapter extension cable that lets you connect the card via a long cable for testing.

    It sounds to me like you have no knowledge of that machine, no test manual and very little machine repair experience. Good luck. :)
     
  7. MrChips

    Moderator

    Oct 2, 2009
    12,442
    3,361
    And that is when it's time to call in R!f@@.
     
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