Does that Bubble on the chip mean it is blown?

Discussion in 'General Electronics Chat' started by Mmasters, May 11, 2014.

  1. Mmasters

    Thread Starter New Member

    May 11, 2014
    1
    0
    This is my first post, so I hope I have done it correctly. The first picture is what I get when the TV first powers up and then after about 10 or 15 seconds the picture comes on and works properly. It will be in that sequence two or three times, then it will do the vertical lines and no picture will come up after the third or fourth power up sequence.

    The second picture shows the chip with a small bubble on it next to the reference indentation, you must look closely to see it. I suspect that means the chip is likely blown or causing the problem. I have thus far replaced the T con board and the capacitors on the power supply board from a Shop Jimmy.Com capacitor kit. These parts were replaced before I noticed the bubble on the chip.

    Does anyone have any experience or a clue as to what may be going on here? Thank You so much for any insight you may be able to provide.


    https://www.dropbox.com/s/lel8vvdvtsefnty/2014-04-24 11.10.24-1.jpg
    https://www.dropbox.com/s/ymb4l7tl676o3s2/2014-05-10 19.44.16-2.jpg
     
  2. MrChips

    Moderator

    Oct 2, 2009
    12,449
    3,365
    I have not seen that bubble before but I believe a fault on the chip would not create that bubble.

    A chip fault would usually cause gross overheating and browning of the writing on the chip.
     
    Mmasters likes this.
  3. Little Ghostman

    Member

    Jan 1, 2014
    294
    97
    I have some old boards with bubbles a bit like that, I have always assumed it was just a mishap in production or done on purpose for some sort of marking.
    A problem to do with a fault seem's unlikely, not a TV but a playstation I had would would be intermittant on powering up, it turned out to be a dry joint. It seems that as it heated up a bit it would cause the joint to connect better, so the problem would look like it was gone.
    It was a nightmare to trace!!! but easy to resolder, I am not saying that is your problem, but intermittent faults can be a you know what to find.
     
  4. THE_RB

    AAC Fanatic!

    Feb 11, 2008
    5,435
    1,305
    Scratch it off, it is probably flux residue. ;)

    The silicon IC inside the chip is nowhere near that bubble, it occupies the centre of the IC package. The outer areas of the IC are where the chip carrier and leads etc are. Even if it is a BGA etc the silicon is much smaller than the package and is in the centre.

    I have seen blown chips "bubbled" up, but it is usually extreme (large flat bubble), with heat discolouring and often cracks, and always in the centre of the package.
    :)
     
    Mmasters likes this.
  5. Little Ghostman

    Member

    Jan 1, 2014
    294
    97
    Well done RB, I totally missed the obvious with the chip in the middle! I saw what you put and had one of those DOH moments!! I have blown the top off enough chips to know whats inside :D.
    I was never sure if the little lumps were on purpose or not, on the boards I have they are all in the same place, but then again maybe the same machine/process just makes it happen that way??????????? Just as well I bet thats a custom chip :D
     
    Mmasters likes this.
  6. ErnieM

    AAC Fanatic!

    Apr 24, 2011
    7,394
    1,607
    Adding a "dot" is common in the industry. A red dot may mean a failed part, other colors may mean some significant process (such as programming a microcontroller) has been performed.

    Usually dots are used only after a large problem is discovered, like 100 units in final that need chips removed to add firmware.
     
    Mmasters likes this.
Loading...