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Sony GDM-F500

Discussion in 'Electronic Repair' started by Jimmy Martin, Feb 21, 2006.

  1. Jimmy Martin

    Jimmy Martin Guest

    The problem is a constant pincushion effect that is concave at left and
    right sides of the screen. I have the schematics for this model. Any ideas
    on what might be causing this? A bad cap? I'll try some freeze spray on a
    few areas.

    jimbo
     
  2. Wayne

    Wayne Guest

    IC007 CXA2043Q is a common failure - results in all sorts of
    deflection-related faults.

    Wayne
     
  3. Jimmy Martin

    Jimmy Martin Guest

    This is a 48 pin surface mount chip. What level of difficulty is it to
    desolder and resolder? Can I use a 30 watt fine tip iron and solder wick for
    this job? I found the chip for $32.99 at WWW.Bluestar-online.com

    I think I will order it and give it a try.

    Jimbo
     
  4. Wayne

    Wayne Guest

    I have done a few of these - just finished one this week. The method I
    use to remove the IC is on page 9 of the REV 1.3 pdf at
    http://www.geocities.com/vk3em/smtguide/smtguide.htm
    (the procedure for Small Outline IC's)
    I find that enameled wire that is .010 dia works best.

    I've done these with a simple 25 watt weller iron with a very fine
    tip, that I filed myself, as my cheapie iron does not have a fine
    enough tip commercially available for it. Before I did my first one,
    four years ago, I practised removing sm ic's from old motherboards.
    Replacing the CXA2043Q requires above average soldering skills, and
    you don't want to damage any of the very fine tracks that the ic is
    soldered to, so if this is your first attempt, better practise ahead
    of time and perfect your tecnique.

    In the ones I've done, a number of the electrolytics near the IC have
    to be removed to give enough room to do the job successfully. On all
    the Sony pcb's that I've done, the pcb's are through-plated, and you
    have to really careful removing the electros so as to not damage the
    pcb. This also requires a good tecnique. What has worked for me is
    this, for each electro.

    1 - add a small amount of flux to the electros two solder pads on the
    bottom of the pcb
    2 - use solder wick to removes most of the obvious solder. You want to
    end up at this point with a partially open (from the bottom of the
    pcb) through-plated hole. The electro will still be firmly soldered to
    the board, however.
    3 - while applying heat to the lead of the electro, again from the
    bottom of the pcb, use a very small jeweller's screwdriver to bend
    the leads of the electro up and away from solder connection to the
    bottom of the pcb
    4 - use needle nose pliers to gently grab the leads of the electro and
    bend the leads close to straight up and down, i.e., perpendicular to
    the pcb.

    In all cases in the process, you have to be careful to not use
    excessive mechanical force or apply too much heat. Some of the plated
    through holes are very small diameter and some of the tracks are very
    thin. Easily damaged!

    5 - now lightly resolder the two electro leads to the pcb, from the
    bottom. the idea here is to add enough solder so the next step works
    well.
    6 - what you now need to do is to use a finger from one hand to
    (gently) rock the electro alternately from one side to the other while
    applying heat to the appropriate lead with your iron, from the bottom
    of the pcb. each gentle push in one direction on the top of the
    electro on the top side of the pcb while heating/melting the solder on
    the appropriate lead from the bottom of the pcb will result in fairly
    quickly levering/extricating the electro out of the pcb, with the pcb
    unharmed.
    7 - once the electro is out, then use your solder wick to remove the
    remaining solder in the through-plated hole. usually this can be done
    from just the bottom, but sometimes going to the top side of the pcb
    is also required. Also you may have to add a bit of solder or flux to
    facilitate removing enough solder from the hole to be able to insert
    the electro (new or reused) for reinstallation after the CXA2043Q has
    finished installation.

    The biggest thing I learned while practising both of the tecniques (IC
    removal/installation and electro removal) was to be gentle and not
    overdo the heat with my soldering iron. The job can be done with
    simple tools, but if you're not experienced, be sure you practice
    ahead of time. Tracks are easily damaged!

    Wayne
     
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