Asus A4L Smoking

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  • rigeback
    Badcaps Veteran
    • Mar 2011
    • 421
    • Malta

    #1

    Asus A4L Smoking

    A buddy got his lap top wet and hooked it up to the power source and the small board where the inlet plug is connected with the sound card started smoking!!
    I was wondering if this is repairable since the mother board might also have some problems! Is there a method of testing the MB to get an idea of the damage??
    All advise much appreciated.
    Attached Files
  • gabik111
    ORD spotter
    • Apr 2011
    • 142
    • USA / Poland

    #2
    Re: Asus A4L Smoking

    First of all use isopropyl acohol to wash all electronic boards that were wet. Let them dry. Put everything together and start searching. Use multimeter to see if there is any power consumption. Look for overheating elements. Everything depends how long laptop was working when get wet. If there was very short time sometimes only washing in alcohol helps. I'm also using heat gun after washing to heat mobo. I was able to recovery 3 out of 4 laptops bathed.
    Laptops and computers repair.

    Comment

    • rigeback
      Badcaps Veteran
      • Mar 2011
      • 421
      • Malta

      #3
      Re: Asus A4L Smoking

      Ok I used WD-40 which is a fairly good moisture inhibiter, I will do a final cleaning with acohol and put it back togeather. The power intake is shorted though as I did check it for contenuity and I think some thing is burnt on the small board near the power source.

      Comment

      • dood
        Deputy dood
        • Mar 2004
        • 2462
        • USA

        #4
        Re: Asus A4L Smoking

        WD-40 on computer components?

        I'm sure it's left behind a thin film on everything you sprayed it on (it's primarily petroleum based...). Now you need to wash the board again, and then wash it with isopropyl alcohol to evaporate the water.
        Last edited by dood; 06-08-2011, 07:08 AM.
        Ludicrous gibs!

        Comment

        • rigeback
          Badcaps Veteran
          • Mar 2011
          • 421
          • Malta

          #5
          Re: Asus A4L Smoking

          Any how the board has been washed off with alcohol and dried off in the sun all afternoon.
          My problem now is to replace the parts that blew nere the power intake in the first photo and its a bummer because the numbers are missing off the transistor, any sugestions to what the replacement ID should be would be great.

          Comment

          • rigeback
            Badcaps Veteran
            • Mar 2011
            • 421
            • Malta

            #6
            Re: Asus A4L Smoking

            Would it be feasible to connect an ATX PSU to the run the mother board??

            Comment

            • gabik111
              ORD spotter
              • Apr 2011
              • 142
              • USA / Poland

              #7
              Re: Asus A4L Smoking

              I wouldn't get that risk. Only original (proper voltage) power supply. Best way to find which components are blown when you get schematic diagram.
              Laptops and computers repair.

              Comment

              • momaka
                master hoarder
                • May 2008
                • 12170
                • Bulgaria

                #8
                Re: Asus A4L Smoking

                Can't tell all that well from the pictures, but it looks like the burned part might be a protection diode (D1?). Above it is what seems like C1. L1 and L3 are coils - they should measure short circuit across.

                I would say start by removing the burned component and see if the short circuit goes away. If not, remove C1 and recheck, then C2 and recheck.

                If there are other parts in that area that I'm not seeing, post them here.
                Last edited by momaka; 06-09-2011, 10:14 PM.

                Comment

                • rigeback
                  Badcaps Veteran
                  • Mar 2011
                  • 421
                  • Malta

                  #9
                  Re: Asus A4L Smoking

                  Yes the short at the power inlet is cured since removing D-1 and coils L-1/2 have contenuity. Will the voltage going to the MB be affected since removing D-1?

                  Comment

                  • rigeback
                    Badcaps Veteran
                    • Mar 2011
                    • 421
                    • Malta

                    #10
                    Re: Asus A4L Smoking

                    I powered the machine up anyway and she's about dead, the fan runs for a few seconds and then shuts down, no post and no screen. When tried with battery fitted not even the fan started, I've got a feeling the battery is doomed as I noticed some cracks in the casing as if it might have been droped????

                    Comment

                    • momaka
                      master hoarder
                      • May 2008
                      • 12170
                      • Bulgaria

                      #11
                      Re: Asus A4L Smoking

                      Originally posted by rigeback
                      Yes the short at the power inlet is cured since removing D-1 and coils L-1/2 have contenuity. Will the voltage going to the MB be affected since removing D-1?
                      If it's just a protection diode, then no.

                      However, since you are not getting a post screen, check what D1 is supposed to be connected to and post back. That way we can see if this is a protection diode or not. If it's not, then this could be the problem why the laptop is not posting.

                      Also check C1 and C2 for short circuit.

                      Comment

                      • rigeback
                        Badcaps Veteran
                        • Mar 2011
                        • 421
                        • Malta

                        #12
                        Re: Asus A4L Smoking

                        Mr. Momaka saving me again! Thanks.
                        D-1 connects to the + pin on the power inlet and the pin out plug and also on the + sides of C1 & C2. The opposite connection of D1 goes to ground and on the - side of C1 & C2 however accross C1 & C2 there is no contenuity which should be correct if they are diodes?
                        I think D1 has something to do with the battery charging lock switch next to the reset button and maybe this is the reason that there was no response when I fitted the battery pack.

                        Comment

                        • momaka
                          master hoarder
                          • May 2008
                          • 12170
                          • Bulgaria

                          #13
                          Re: Asus A4L Smoking

                          Originally posted by rigeback
                          D-1 connects to the + pin on the power inlet and the pin out plug and also on the + sides of C1 & C2. The opposite connection of D1 goes to ground and on the - side of C1 & C2 however accross C1 & C2 there is no contenuity which should be correct if they are diodes?
                          C1 and C2 are ceramic capacitors (as indicated by the "C" prefix). No continuity across C1 and C2 is good. If the "-" side of C1, C2, and D1 are connected to ground, though, then D1 was indeed a protection diode. Therefore, it's possible that other things may have been damaged when this laptop got wet.

                          Originally posted by rigeback
                          I think D1 has something to do with the battery charging lock switch next to the reset button and maybe this is the reason that there was no response when I fitted the battery pack.
                          I guess we could double-check the function of D1 - just post another more focused picture of that area, if possible.

                          Originally posted by rigeback
                          Mr. Momaka saving me again!
                          Well, not quite yet, but I like to try .

                          Comment

                          • rigeback
                            Badcaps Veteran
                            • Mar 2011
                            • 421
                            • Malta

                            #14
                            Re: Asus A4L Smoking

                            Here are few more picks of the area, asus recomends that the battery lock
                            CE-1 is in place every time the base & battery is removed!
                            Attached Files

                            Comment

                            • momaka
                              master hoarder
                              • May 2008
                              • 12170
                              • Bulgaria

                              #15
                              Re: Asus A4L Smoking

                              Still hard to tell what D1's function is. Board is messy in that area and I can't see which side should be the cathode (cathode side is usually marked with a thick white line on the PCB - see if you can see it and let me know).

                              There's another component under D1. What is it? Also, where does that white connector lead to? Main board? If so, check any components that are connected to it on that board.

                              As for switch CE1 - try it in both positions.

                              Comment

                              • rigeback
                                Badcaps Veteran
                                • Mar 2011
                                • 421
                                • Malta

                                #16
                                Re: Asus A4L Smoking

                                D1 goes to that switch in postion unlock which I guess is charging mode, the thicker white line is on the board I think although in the first pic there is no indication on the good side of D1 it could be on the white connector side???
                                Yes the white connetcor goes to the MB which seems to be okay. Under D1 there is C28 which seems to be a coil as there is continuety across and this connects to the lower part of the card near the USB area.
                                If the AC power to this area is 19V what sort of resistance should I be looking for if I replace the diode, I got one simular size that reads 24.4oms??

                                Comment

                                • momaka
                                  master hoarder
                                  • May 2008
                                  • 12170
                                  • Bulgaria

                                  #17
                                  Re: Asus A4L Smoking

                                  Originally posted by rigeback
                                  Under D1 there is C28 which seems to be a coil as there is continuety across and this connects to the lower part of the card near the USB area.
                                  C28 would be a capacitor then, not a coil.

                                  Again a "C" prefix means the component is a capacitor. An inductor or a coil would have an "L" prefix. Resistors have "R". Diodes have "D". That's how you know what the parts on the board are.

                                  If the part in question under D1 really is C28, then it is a capacitor. Since you said it's showing a short circuit across, then you will need to remove it from the board and test it out of circuit. A good ceramic capacitor will show open circuit when it's removed from the board.

                                  As for D1 - well, if the pad closest to the white connector is connected to switch CE1, then D1 is not a protection diode. In that case, a new diode should be placed with the cathode (white stripe on the diode) closer to the white connector.
                                  I'm not sure what the replacement for diode D1 should be, but judging by the size of the burned diode, a new diode rated for 3 Amps or more should be enough. If you don't have any surface mount diodes, just use a regular axial diode - should be fine for testing.

                                  Originally posted by rigeback
                                  If the AC power to this area is 19V what sort of resistance should I be looking for if I replace the diode, I got one simular size that reads 24.4oms??
                                  You pick diodes by the Ampere rating. The ampere rating can be obtained from the diode's data sheets only (or estimated by their physical size when you have more experience with them).

                                  The resistance you measured on the diode won't really tell you anything, because diodes, unlike resistors, are not linear devices and will have different resistances at different currents. So to answer your question - you can't use your multimeter to determine what the replacement diode should be.

                                  A 3A diode should be enough, though. If you have any junk electronics (particularly power supplies), you may find one in there.
                                  Last edited by momaka; 06-14-2011, 09:33 PM.

                                  Comment

                                  • rigeback
                                    Badcaps Veteran
                                    • Mar 2011
                                    • 421
                                    • Malta

                                    #18
                                    Re: Asus A4L Smoking

                                    Yes the 3A Diode has been replced from another junked PC and I thought I would give it a whirl before removin C28, connected the power and nothing happened then I noticed that the light on the power supply was off, this is board is dumping the power supply sice replacing the diode.

                                    I will proceed to remove C28 although the soldering space is very limited for a piece so small!

                                    Comment

                                    • rigeback
                                      Badcaps Veteran
                                      • Mar 2011
                                      • 421
                                      • Malta

                                      #19
                                      Re: Asus A4L Smoking

                                      Oops, D1, C1 & C2 do Not connect with CE1 switch. also C28 does not connect to D1 therefore I guess D1 might be a protection diode as you said!

                                      Comment

                                      • rigeback
                                        Badcaps Veteran
                                        • Mar 2011
                                        • 421
                                        • Malta

                                        #20
                                        Re: Asus A4L Smoking

                                        Well strange things happen, I changed the diode out with a different one today and after testing everything I reconnected and shes posting, in the process of reinstalling xp without a battery though!! Good enough for this machine and good enough for me.

                                        Comment

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