Connect with us

capacitor

Discussion in 'General Electronics Discussion' started by adrian polley, Feb 3, 2016.

Scroll to continue with content
  1. adrian polley

    adrian polley

    8
    1
    Feb 2, 2016
    hi all.
    im new to this forum hoping to get some help/ advice.
    i have a 46' lcd samsung tv. it has the very common wont turn on clicking.
    i have watched heaps of you tube vids and read many forums bout this symptom and result is the same 95% of the time. change out the capacitors.
    so i went ahead and done this and the tv is the same.
    any ideas? what am i missing?
     
  2. davenn

    davenn Moderator

    13,901
    1,971
    Sep 5, 2009
    hi there

    welcome to EP :)

    so specifically what caps did you replace ?
    show some sharp and well lit photos
     
  3. adrian polley

    adrian polley

    8
    1
    Feb 2, 2016
    i changed these 7 caps.
    only one looked blown, but changed them all anyway.
    one thing im not sure of though, are the blue ones in the middle capacitors, or are they something else?
    how do i tell if they are bad.

    thanks
     

    Attached Files:

  4. davenn

    davenn Moderator

    13,901
    1,971
    Sep 5, 2009
    OK

    those 3 blue things are inductors, unlikely to be related to the problem

    Now assuming that you were VERY CAREFUL in making sure that your replaced the caps with the correct values and voltage ratings
    then we need to look elsewhere for the problem

    I was to see a sharp and clear ( this time) pic of the area to the left of the heatsink

    all inside the red square component and track sides of the board

    there are 2 fuses to check also, they are inside the 2 blue squares
    ( the one in the lower right is likely to be OK)

    xx.jpg



    Dave
     
  5. 73's de Edd

    73's de Edd

    3,224
    1,349
    Aug 21, 2015
    .


    Sir Adrian Polley . . . . .



    Here is a mo' bettah, big blow up of that same board , with the very hardest taxed capacitors tagged by RED DOTS.

    The next most likely are the ones associated with the controller circuitry, if acting squirrelly or having erratic turn on or
    shutdown, being marked by BLUE DOTS.

    Least likely suspect, are the center of the PCB, raw DC line supply capacitors with GREEN DOTS.

    Note . . . in addition to the central and lower right standard ceramic cased clip in fuses, just outside of the right top corner of the previously mentioned blue box, is ICP802 , circuit protector, which one might confuse with being a transistor, unless you notice that it only has 2 leads..


    [​IMG]



    73's de Edd

    .
     
    Last edited: Feb 3, 2016
  6. adrian polley

    adrian polley

    8
    1
    Feb 2, 2016
    thanks guys for your help.

    davenn, here is a closer view of the area you asked for.
    i cant visually see anything wrong.
    both the fuses you mentioned are ok.

    73 de ed, are you suggesting change out the blue dot caps? and icp802?
    thats no biggie if you reckon its worth a shot.
    how far do i take this before i decide to chuck it and get new tv? before i know it i could have changed half the board to no avail.
     

    Attached Files:

  7. davenn

    davenn Moderator

    13,901
    1,971
    Sep 5, 2009
    OK ... but you still haven't shown the track side of the board ... I want to look for dry joints


    Yes, a real good idea :)

    I cant see that on the board ??

    Edit: OK found it ;) --- what is that device ? can you read the markings on it ?

    if it has 2 legs, it's probably a fuse and you can test it as such


    Dave
     
  8. adrian polley

    adrian polley

    8
    1
    Feb 2, 2016
    davenn
    thanks for getting back so quick.
    sorry im not a tech guru so didnt know what you meant by track side.
    so i turned it over and looked carefully. i took photos of what appears to be a heat affected area. looks like coffee spilled. (but didnt)
    so i took close ups of this area.
    when i look close, it looks as though the solders in this area have slight corrosion around the edges.
    the affected area is exactly where the heat sink in the red square is.

    icp802 has no markings at all and has 3 legs
     

    Attached Files:

  9. adrian polley

    adrian polley

    8
    1
    Feb 2, 2016
    so im guessing noone has any idea.
     
  10. davenn

    davenn Moderator

    13,901
    1,971
    Sep 5, 2009
    welllllll ..... we were waiting for you to tell us what happened after you replaced the 5 caps with the blue dots

    you are being taken through the cheaper choice of repair first
    after that it will likely get both costly and difficult

    There's the possibility that there may be no fault with the PSU board and it is just reacting to a fault on another board that is loading down the PSU
     
  11. adrian polley

    adrian polley

    8
    1
    Feb 2, 2016
    oh.
    i thought once i mentioned what looks like corrosion you would probably say chuck it out and get new tv.
    i will change out those caps and get back to you

    thanks
     
  12. davenn

    davenn Moderator

    13,901
    1,971
    Sep 5, 2009
    I see a little solder flux here and there .... no signs of obvious corrosion
     
  13. adrian polley

    adrian polley

    8
    1
    Feb 2, 2016
    blue dot caps changed out. still the same.
    i think its time to just cut losses, chuck it and get new one.
     
    davenn likes this.
  14. davenn

    davenn Moderator

    13,901
    1,971
    Sep 5, 2009
    Sometimes it's the cheapest way to go after checking out the common faults :)
     
  15. 73's de Edd

    73's de Edd

    3,224
    1,349
    Aug 21, 2015
    Sir Adrian Polley . . . . .


    My self., I would want to know some rudimentary initial measurements and output levels.
    First was that ICP testing out like having a short between two of its leads ?

    I NEVER have seen one with 3 leads unless the center lead is custom formed to be connected to one side lead.

    One-a-them-looka-like-a-this:

    [​IMG]

    Then you would expect a good CP to be shorted between the paired leads AND the single wire lead, if its being an unblown unit.

    Considering all fuses and that CP to be good, the very first test would be to see if you have basic raw DC voltage across the
    center of the PCB's two 100 @ 450VDC black electrolytics. Testing across their +- terminals
    If that power is present it flows up the board to the power switching device on the smaller top left heat sink
    Pass me its part number , since the only number I can make out is the CM/N 814 ceramic capacitor mounted in front of it

    Its drive level for initiating and sustaining its power switching is being from the 8 pin ICM801
    Pass on its number, since I believe that it is being a newer number, deviating from our expected usual 3 IC types.
    To the right side of your YELLOW, central power switch mode transformer is where your lower supply voltages are being
    created and passing to the right to the two DM8XX series of diodes which rectify and pass voltages to your cluster of RED dotted electrolytics.
    Your foil side photos were not bright or clear enough for me to work with, but the majority of all of those electrolytics negative terminals will be tied
    together and be the basic negative buss of your secondary power supplies.
    Also I believe that most voltages will be marked beside the two BLACK right side connectors, B UT being QUITE hard to probe with plugs connected.
    BUT you could take MOST of those readings from the 8 or so BARE jumper wires being juxtaposed between connections on the top side of the board.
    For grins . . .to see if theres being ANY activity from the switch mode supply initially research to find your common ground negative metering
    point and then have all of the system plugged in and connected up and go to DC measurement mode and power up the set. to see if there is any
    voltage presence at any of the jumpers. There just might be one little standby voltage present.

    Thasssit . . . . .until I see what the ICM801 is, in order to tell you what pins to check for power presence and a test of its drive output from it, by using your meters AC mode

    One last item . . .just at the bottom of the right heat sink, below the spaced apart BLACK power schottky . . . . . (hmmmmmmmm spel chek is tellin' me Scottish !) . . . . rectifier
    cases, confirm for me that the bottom ICM ??? is having 431 in its numbering scheme.



    73's de Edd
     
Ask a Question
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Electronics Point Logo
Continue to site
Quote of the day

-