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Which way does it go????

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    #1

    Which way does it go????

    Hello Everyone,

    I have a big problem with my ECS 661FX-M motherboard. It was working fine before my younger brother decided to get the handle of a screw driver and hit it against the board a few times. I picked the board off him only to find that he broke the solder joints off an SMT cap right under the SiS 661FX northbridge.

    The SMT cap fell off the board as a result. It looks fine to me but theres only one problem. I don't know which way the cap goes, there no markings, nothing. I think they are Bi- Directional, but I want to make sure before I blow my CPU or RAM chip. I will have to resolder it back onto the board soemhow.... maybe I have to use a needle point tip this time and also .3 mm solder wire.



    Thanks.
    Don't find love, let love find you. That's why its called falling in love, because you don't force yourself to fall, you just fall. - Anonymous
    Tags: None
    #2
    Re: Which way does it go????

    SMT caps are usually mylar or tantalum caps, and are non-polar. To double check, look at the silkscreen under the cap and see if there's any markings. If not, its not polarized.
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      #3
      Re: Which way does it go????

      If there are absolute no markings, it is probably an MLCC, wich are non polarized.
      Tantalums are polarized, but usually they`r marked accordingly.

      Comment

        #4
        Re: Which way does it go????

        I just had another search on the internet for this surface mount component and it is actually called a multilayer SMD ceramic chip capacitor. I have attached an image of a similar one which I found on the internet.
        Attached Files
        Don't find love, let love find you. That's why its called falling in love, because you don't force yourself to fall, you just fall. - Anonymous

        Comment

          #5
          Re: Which way does it go????

          Yup, MLCC.

          Comment

            #6
            Re: Which way does it go????

            Hello Everyone,

            I have good news after soldering the SMT cap back onto the board.

            IT WORKS!!!!

            After I soldered it two weeks ago, I haven't had time to boot it up etc. until 10 minutes ago when I took a stick of 512MB DDR RAM out of my media center PC and a Celeron 2GHz CPU out of another PC.

            I was expecting an explosion or something similar to happen when I booted it up, but I was really happy to see the POST messages on the screen.

            It is currently powered by my testbench DEER Power supply. I have to recap this Deer PSU soon before it blows something up....

            The voltages on the board seem quite stable with the CPU Vcore at 1.50V and the DDR voltage at 2.60V. The CPU temperature is at 33 degrees celcius which is good.

            I will probably install this ECS motherboard in the Acer Veriton 5200D case which I found on the footpath 2 weeks ago.

            Theres only one design flaw with this board and that is the fact that I cannot connect a 3 pin power LED to the motherboard. It only accepts 2 pin LEDs. The Acer case has a 3 pin power LED with 3 wires.... it probably means that it is a dual colour LED????

            There is a "Turbo"LED for that case and is two pins.... would it be OK to use that one?? I dont want to burn out the front panel header or something like that....



            Thanks.
            Last edited by stevo1210; 05-04-2007, 10:51 PM.
            Don't find love, let love find you. That's why its called falling in love, because you don't force yourself to fall, you just fall. - Anonymous

            Comment

              #7
              Re: Which way does it go????

              Who cares about stupid LEDS, I'm not even sure whether it's healthy to have them beaming in your eyes all day, I know I feel physically sick when I stare at lots of LEDS for long periods, power on and reset, thats all thats needed.
              Rubycon Rubycon Rubycon

              Comment

                #8
                Re: Which way does it go????

                It's been a few months since I last touched this motherboard, but I just noticed that the solder that's holding the MLCC onto the board is a dull grey colour??
                Do I have a cold solder joint??
                One side of the MLCC has shiny solder, other side has dull, grey coloured solder and a small hole/ bubble thing in the solder??....
                Are cold solder joints a bad thing??
                Don't find love, let love find you. That's why its called falling in love, because you don't force yourself to fall, you just fall. - Anonymous

                Comment

                  #9
                  Re: Which way does it go????

                  Yup, cold solder joints are bad - just reflow it, if necessary adding a droplet of good 60/40 or 63/37 solder.

                  Comment

                    #10
                    Re: Which way does it go????

                    um.... yeah, I cleaned up all the solder with a soldering braid and resoldered it.... it's a bit off center though, but that isn't major.

                    I have a small problem though. On the PCB, while removing the MLCC solder, I slipped with the soldering iron and scratched two traces. The board still boots etc. AGP and PCI ports work etc.

                    The traces which I accidentally scratched have something silver exposed. The purple colour paint on the PCB (which is supposed to cover the traces) is gone and I can see a portion of silver. Is the silver colour the actual trace or is it something much more serious??

                    I checked by putting a soldering braid over it and checking if it was solder and it definitely isn' t solder....

                    Thanks.
                    Last edited by stevo1210; 07-17-2007, 06:33 AM.
                    Don't find love, let love find you. That's why its called falling in love, because you don't force yourself to fall, you just fall. - Anonymous

                    Comment

                      #11
                      Re: Which way does it go????

                      I have just learnt that I probably damaged the solder mask on the traces. Is there a way to fix the damaged solder mask??.

                      Thanks.
                      Don't find love, let love find you. That's why its called falling in love, because you don't force yourself to fall, you just fall. - Anonymous

                      Comment

                        #12
                        Re: Which way does it go????

                        Dont worry about it if its just the Green or Blue sitting on top
                        The only real worry is, if and how bad this may be when you dig into the copper in a big way

                        Sometimes when trouble shooting people may be forced to cut tracks and its simply a matter of scratching back the solder mask and soldering it back together (bridging)

                        So if you haven't done any major damaged to the copper don't worry about it.

                        If you are worried about it tarnishing I think you can get circuit board Lacquer at jaycar CAT. NO. NA1002 spray on $10 a can

                        there are other methods like vanish can't recall whats best, KC8 would probably know.


                        Cheers
                        You step into the Road, and if you don't keep your feet, there is no knowing where you may be swept off to." Bilbo Baggins ...

                        Comment

                          #13
                          Re: Which way does it go????

                          Originally posted by starfury1
                          Dont worry about it if its just the Green or Blue sitting on top
                          The only real worry is, if and how bad this may be when you dig into the copper in a big way
                          It was only the blue/purple stuff on the top that came off, the two silver traces underneath are still there. I don't know why the traces are silver though, isn't copper supposed to be gold in colour??

                          I tested the board yesterday night and it booted perfectly with the onboard video etc. so i can definitely confirm that the trace isn't broken.

                          Originally posted by starfury1
                          If you are worried about it tarnishing I think you can get circuit board Lacquer at jaycar CAT. NO. NA1002 spray on $10 a can

                          there are other methods like vanish can't recall whats best, KC8 would probably know.
                          The tarnishing was what I was worried about most. Looks like i'll have to buy a can of that lacquer.... I never knew anything like that existed lol.
                          Lucky for me, I could walk to the Jaycar near my house.

                          Just wondering.... is that lacquer going to be conductive or corrosive in the long run??

                          Thanks.
                          Last edited by stevo1210; 07-30-2007, 05:37 AM.
                          Don't find love, let love find you. That's why its called falling in love, because you don't force yourself to fall, you just fall. - Anonymous

                          Comment

                            #14
                            Re: Which way does it go????

                            Is the laquer just a clear coating?? or does have some colouring in it too??

                            Thanks.
                            Don't find love, let love find you. That's why its called falling in love, because you don't force yourself to fall, you just fall. - Anonymous

                            Comment

                              #15
                              Re: Which way does it go????

                              Bugger lost what I typed

                              Anyway Tin plating will have a silver look but not sure if they would do this to MB's

                              Copper has a bright brownie look, sometimes they gold plate things too

                              From the doc that caused me to lose everything id typed

                              Circuit Board Protective Clear Lacquer.

                              and from the jaycar site


                              Circuit Board Lacquer Spray Can

                              Non CFC Ozone safe propellant. Premium quality flexible coating to protect printed circuit boards from humidity and environmental attack. Special solder through lacquer so previously coated boards can be soldered.

                              I understand why you asked ...you don't want a multi coloured PCB

                              you wont need to spray the whole pcb just the area thats scratched
                              (mask it with paper / tape for a cleaner look if you like) .

                              it shouldn't be conductive and shouldn't be corrosive it was designed for this purpose.

                              Hope this helps.....nice to have a store near you
                              (mine are miles away)

                              Cheers Mate
                              You step into the Road, and if you don't keep your feet, there is no knowing where you may be swept off to." Bilbo Baggins ...

                              Comment

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