Capacitor Plague?

Discussion in 'The Projects Forum' started by genericlifeform, Sep 4, 2009.

  1. genericlifeform

    Thread Starter New Member

    Sep 4, 2009

    I have a pair of identical monitors: one has gone bad and the other has a transient when you first turn it on (flickers for about 20 seconds), which I interpreted as it was about to go bad too. So I took apart the monitors to look for signs of capacitor plague.

    I found some white substances near the capacitors (please see attached pics) which I thought might be leaking dielectric, but all the pictures I've found of capacitor plague show caps with distressed vent-domes -- which mine don't have -- and they don't show the white substance.

    The only other thing I can think of is that its some kind of glue, but I have no idea why you'd need to glue down a component in a monitor...

    If anyone can confirm that these capacitors are indeed bad, I'd be appreciative.


    [First pic is from signal processing board; second is from the power supply board]
  2. SgtWookie


    Jul 17, 2007
    In the left pic, glue was used to anchor the toroidal inductors to the board. They have a fair amount of mass, and anchoring them down is necessary to keep them from breaking loose during shipping.

    In the right photo, I can't see detail of the item boxed in on the lower left.
    The other two look like adhesive was deliberately applied. The rightmost cap looks like it has a flat top (OK), but the glare makes it difficult to be sure. You might want to carefully remove the adhesive from the top of the upper left cap to see if it's bulging.

    AAC Fanatic!

    Jul 1, 2008
    As a side note, as it has nothing to do with your cap question, adhesives are used for other reasons also. Oscillators, for example, may use it to reduce the tendency to FM do to shock and vibration.
  4. THE_RB

    AAC Fanatic!

    Feb 11, 2008
    Buy (or build) an ESR meter, that tests the caps. Then you will never again have to guess if a cap is bad. :)