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Coffee Machine - YAY! I've blown my first capacitor (and a tip or two from a Newbie!)

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    Coffee Machine - YAY! I've blown my first capacitor (and a tip or two from a Newbie!)

    Following my fridge post yesterday, I thought I would try desoldering.

    I have a coffee machine which didn't switch on.

    I could see C5 cap was blown so got another faulty board and desoldered the capacitor from that. Took me a good 30 minutes or so to remove my first ever cap. If anyone hadn't done this before, watch a few videos on YouTube first.

    I doubt it is the best way to do it but I found lightly gripping the capacitor with a pair of pliers and loading the leads with fresh lead eventually worked.

    First off I tried desolder braid on each leg individually. Man! That wastes so much time and resulted in failure.

    When I finally removed cap, I checked it and it was within tolerance. Tools are important here ESPECIALLY if you are a newbie. I went out and bought solder braid and a no clean flux pen.

    I wiped over the legs (which still had solder residue on with the flux pen). One leg would not go through the one hole so I located it and went over both solder pads with the flux pen and the mask in between.

    I loaded up the iron and wipe back and forth across the holes whilst pressing the capacitor up towards the holes and seconds later pop, it seated and two defined pads of solder appeared! Brilliant! Well chuffed.

    Now this is where I need advice.

    I plugged the PCB back into coffee machine in workshop. Worked back to house and plugged in, reset and activate trip switch then reset again.

    Walked back out to workshop (15 seconds) and the replaced capacitor was smoking. Switched off quick before it blew.

    The coffee machine does not heat the thermoblock until you press a button so this circuit is live even though the machine appears not to be switched on. Not sure if that will give anyone any further clues.

    On closer inspection, the blue resistor doesn't look too good.

    Do any of the experts on here think that this could have caused the original failure and subsequent failure of the cap?

    Capacitor is rated at 400V 2.2uF. Polarity was respected when recapping. Remember! I'm a newbie at this sort of stuff.

    Can anyone tell me the rating of the blue resistor? I have used an app to try and identify it but I am not clear on which end to start from. I tried both but not convinced at result which states 47 Ohms 1% but one on new board, in-circuit measures 17.8 Ohms?
    Attached Files

    #2
    Re: Coffee Machine - YAY! I've blown my first capacitor (and a tip or two from a Newb

    c5 is bad, the top is domed.

    the blue resistor should meter 4.7 ohms i think.
    you need to meter it for resistance - the peak esr meter can probably do it although it's not intended for that.

    Comment


      #3
      Re: Coffee Machine - YAY! I've blown my first capacitor (and a tip or two from a Newb

      I agree c5 should be replaced. I'd check c8 too.

      The resistor is 47 ohms, 5%. Check it out of circuit.

      Comment


        #4
        Re: Coffee Machine - YAY! I've blown my first capacitor (and a tip or two from a Newb

        Originally posted by SteveNielsen View Post
        I agree c5 should be replaced. I'd check c8 too.

        The resistor is 47 ohms, 5%. Check it out of circuit.
        C8 is fine in circuit. I need to trust the Peak. However, I checked the resistor on the new PCB and it measured 17.8 Ohms ESR in circuit but the marking appear to be 47 Ohms hence the confusion.

        The resistor on the broken board measures open with the Peak and as does C5.

        What I am looking for is a reason why C5 would go from fine to open circuit in 20 seconds! Would the resistor have caused that because I had not noticed the resistor missing some of its covering before powering the board back up after having replaced C5?

        Comment


          #5
          Re: Coffee Machine - YAY! I've blown my first capacitor (and a tip or two from a Newb

          Originally posted by SteveNielsen View Post
          The resistor is 47 ohms, 5%
          no it's not, it has a final brown stripe = 1%
          the gold is a divisor.

          Comment


            #6
            Re: Coffee Machine - YAY! I've blown my first capacitor (and a tip or two from a Newb

            http://www.ankaudiokits.com/resistorcodes.html

            Comment


              #7
              Re: Coffee Machine - YAY! I've blown my first capacitor (and a tip or two from a Newb

              You're right, it's 1%, my mistake.

              Comment


                #8
                Re: Coffee Machine - YAY! I've blown my first capacitor (and a tip or two from a Newb

                Originally posted by Rhothgar View Post
                C8 is fine in circuit. I need to trust the Peak. However, I checked the resistor on the new PCB and it measured 17.8 Ohms ESR in circuit but the marking appear to be 47 Ohms hence the confusion.

                The resistor on the broken board measures open with the Peak and as does C5.

                What I am looking for is a reason why C5 would go from fine to open circuit in 20 seconds! Would the resistor have caused that because I had not noticed the resistor missing some of its covering before powering the board back up after having replaced C5?
                Just to make sure it's understood, checking components in circuit is fine for quick trouble-shooting but readings are often altered by other connected components in circuit. To be sure the parts should be tested out of circuit.

                Without seeing a schematic my educated guess is yes the open resistor could have caused the cap to fail, however the cap may have been ready to fail anyway so it could have been a combination of factors.

                Comment


                  #9
                  Re: Coffee Machine - YAY! I've blown my first capacitor (and a tip or two from a Newb

                  looking at the board,
                  i would start by checking all the diodes for shorts.

                  Comment


                    #10
                    Re: Coffee Machine - YAY! I've blown my first capacitor (and a tip or two from a Newb

                    Originally posted by SteveNielsen View Post
                    Just to make sure it's understood, checking components in circuit is fine for quick trouble-shooting but readings are often altered by other connected components in circuit. To be sure the parts should be tested out of circuit.
                    Understood.

                    Originally posted by SteveNielsen View Post
                    Without seeing a schematic my educated guess is yes the open resistor could have caused the cap to fail, however the cap may have been ready to fail anyway so it could have been a combination of factors.
                    Cap tested fine out of circuit and appeared to be within tolerance.
                    Last edited by Rhothgar; 05-30-2015, 01:17 PM.

                    Comment


                      #11
                      Re: Coffee Machine - YAY! I've blown my first capacitor (and a tip or two from a Newb

                      Originally posted by stj View Post
                      looking at the board,
                      i would start by checking all the diodes for shorts.
                      I'll check those too.

                      I've borrow a book of a friend entitled "How to fix everything electronic". It appears at first glance to be broken down into a nice understandable format for the likes of me.

                      Comment


                        #12
                        Re: Coffee Machine - YAY! I've blown my first capacitor (and a tip or two from a Newb

                        Originally posted by stj View Post
                        looking at the board,
                        i would start by checking all the diodes for shorts.
                        I have found a diode which is showing .375 in circuit both ways.

                        All the others are showing 0.62 or thereabouts in circuit and OL in other direction.

                        The diode D1 is copper coloured looking. Is this a Zener diode? It is tiny! How can I find out what specification it is please?

                        Comment


                          #13
                          Re: Coffee Machine - YAY! I've blown my first capacitor (and a tip or two from a Newb

                          D1 looks to be a GS1M, which is a 1A rectifier diode.

                          Comment


                            #14
                            Re: Coffee Machine - YAY! I've blown my first capacitor (and a tip or two from a Newb

                            lift one end and test it again.

                            Comment


                              #15
                              Re: Coffee Machine - YAY! I've blown my first capacitor (and a tip or two from a Newb

                              Originally posted by SteveNielsen View Post
                              Just to make sure it's understood, checking components in circuit is fine for quick trouble-shooting but readings are often altered by other connected components in circuit. To be sure the parts should be tested out of circuit.
                              Oh, please. If we all had to remove the parts from every pc board we would never get anything fixed, let alone designed. It is actually faster to replace all the parts at once with no testing whatsoever. Pretty obvious what happened in this case, judging by the appearance of one capacitor and one resistor.
                              Is it plugged in?

                              Comment


                                #16
                                Re: Coffee Machine - YAY! I've blown my first capacitor (and a tip or two from a Newb

                                The Blue rectangular X/Y cap, do each one of the legs connected to Line and Neutral? That cap looks to be connected in parallel with the MOV.
                                That big Metal Oxide resistor (Red, ?,?,? bands) looks to be for dropping resistor and looks like it got hot, D1 is the rectifier for generating DC for the running the circuit.
                                Is the Lytics brown cap (c?) next to C5 rated at 2.2uF 400VDC also?
                                Last edited by budm; 06-03-2015, 10:04 AM.
                                Never stop learning
                                Basic LCD TV and Monitor troubleshooting guides.
                                http://www.badcaps.net/forum/showthr...956#post305956

                                Voltage Regulator (LDO) testing:
                                http://www.badcaps.net/forum/showthr...999#post300999

                                Inverter testing using old CFL:
                                http://www.badcaps.net/forum/showthr...er+testing+cfl

                                Tear down pictures : Hit the ">" Show Albums and stories" on the left side
                                http://s807.photobucket.com/user/budm/library/

                                TV Factory reset codes listing:
                                http://www.badcaps.net/forum/showthread.php?t=24809

                                Comment


                                  #17
                                  Re: Coffee Machine - YAY! I've blown my first capacitor (and a tip or two from a Newb

                                  This is what I can tell based on the pictures.
                                  Attached Files
                                  Last edited by budm; 06-03-2015, 03:55 PM. Reason: Fixed the connections
                                  Never stop learning
                                  Basic LCD TV and Monitor troubleshooting guides.
                                  http://www.badcaps.net/forum/showthr...956#post305956

                                  Voltage Regulator (LDO) testing:
                                  http://www.badcaps.net/forum/showthr...999#post300999

                                  Inverter testing using old CFL:
                                  http://www.badcaps.net/forum/showthr...er+testing+cfl

                                  Tear down pictures : Hit the ">" Show Albums and stories" on the left side
                                  http://s807.photobucket.com/user/budm/library/

                                  TV Factory reset codes listing:
                                  http://www.badcaps.net/forum/showthread.php?t=24809

                                  Comment


                                    #18
                                    Re: Coffee Machine - YAY! I've blown my first capacitor (and a tip or two from a Newb

                                    budm have you got c5 and l1 mixed up? im new to all this was just looking and trying to learn the circuits im using the picture in post 1 im probaby completly wrong though.

                                    Comment


                                      #19
                                      Re: Coffee Machine - YAY! I've blown my first capacitor (and a tip or two from a Newb

                                      I drew the line wrong so I need to fix that, thanks for seeing that, I have been flipping the virtual PCBA back and forth many times now.
                                      It is fixed now.
                                      Last edited by budm; 06-03-2015, 03:52 PM.
                                      Never stop learning
                                      Basic LCD TV and Monitor troubleshooting guides.
                                      http://www.badcaps.net/forum/showthr...956#post305956

                                      Voltage Regulator (LDO) testing:
                                      http://www.badcaps.net/forum/showthr...999#post300999

                                      Inverter testing using old CFL:
                                      http://www.badcaps.net/forum/showthr...er+testing+cfl

                                      Tear down pictures : Hit the ">" Show Albums and stories" on the left side
                                      http://s807.photobucket.com/user/budm/library/

                                      TV Factory reset codes listing:
                                      http://www.badcaps.net/forum/showthread.php?t=24809

                                      Comment


                                        #20
                                        Re: Coffee Machine - YAY! I've blown my first capacitor (and a tip or two from a Newb

                                        im new to trying to read these sort of things so good practice for me too,a easy mistake to make when going through all the pictures.Its good to see how you can draw these circuits out, i can see Now why now you ask for good clear picures.

                                        Comment

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