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    DC Ceiling Fan Motor Controller / receiver

    Hi All,

    I'm having a problem with a DC ceiling fan controller (from a Mercator Trinidad fan). This operates via a remote. The light works fine, as does re-pairing the remote (an audible beep is emitted). The fan function itself however does not. This leads me to believe the issue is more than likely with the DC power control part of the circuit. I have another known good controller for comparison.

    When it first started having issues - and this might be key to forming a theory from someone more experienced than I - it initially wouldn't work until after the AC isolator wall switch was on for some time - sometimes even taking a few hours from pressing a fan speed button on the remote until the fan actually started turning.

    I suspected capacitor issues originally, due to it having some lag time before it would work. Here are some pics - visually all seems okay.






    Electrolytic caps;

    - The big 68uf 450v cap tested ok. Had .29ohm esr and .7% vloss.
    - 100uf 16v tested ok, .49ohm esr and 4.1% vloss
    - 100uf 35v tested ok, .07ohm esr and 1.4% vloss
    - 47uf 35v tested ok

    Film caps;
    - cx2 - .1uf film cap tested at 70.3nf .40 esr
    - cx1 - same as above, 89.1nf .29 esr

    Interestingly, I swapped these over and the fan had not worked even being on for hours like it did before, even after swapping them back.

    *The whole input bank (inductors(?)+film caps) in circuit from the AC input wires (brown/blue) to the bridge rectifier measures 164uf (vs 154uf on the good fan control )) - 8.4/7.4 esr respectively, so I'm not sure that even though the film caps are >10% outside spec that this would fix it, particularly as the bad one has a higher capacitance reading.

    Diodes;
    - Tested all surface mount diodes okay, however. D7 was open both ways.
    - D7 is S1J. removed from circuit - tested ok - reinstalled.

    Bridge Rectifier;
    - bridge rectifier is KBP08. Tested 240vac in, 318vdc out.

    Test Points;

    Tp0+tp1 = 15vdc (correct supply voltage for PCM as per PDF below)
    Tp0+tp2 = 3.5vdc
    Tp0+tp3 = 320vdc (correct DC bus voltage)
    Tp0+tp4 = continuity, GND(?)
    Tp0+tp5 = .5vdc ***Noted that this on the good controller is 3.5vdc - this is the only difference I've measured.
    Tp0+tp6 = .5vdc
    Tp0+tp7= 15vdc (when light is 'off' only, activates light relay)

    Has irsm836-025ma dc power control module https://cdn.badcaps-static.com/pdfs/...33a5dc8694.pdf

    Tp5 and Tp6 correspond to pins 5 and 6 on the dc power control module, and the description from the datasheet is;

    5 | /FLT | Fault Output Pin
    6 | Itrip | Over-Current Protection Pin

    Focussing on pin 5, and the description for fault in the datasheet "Once the fault condition occurs, the FAULT pin is internally pulled to VSS and the fault clear timer is activated. "

    VSS is described as " 9, 39 | VSS, COM | Ground for Gate Drive IC and Low Side Gate Drive Return "

    Should I be interpreting that as it's been pulled to ground (hence the .5v reading vs the 3v on the good controller) therefore it's detecting a fault?

    I've hit a bit of a wall here - any suggestions that may help me out?


    Also - for the DC motor feed wires (U/V/W) I get 2v out of U/V/W +gnd and 26v from tp3(dc bus voltage)+U/V/W.
    Last edited by 265chemic; 01-13-2020, 08:29 PM. Reason: images

    #2
    Re: DC Ceiling Fan Motor Controller / receiver

    I cannot see any pictures.
    please use that attachment to upload the pictures instead.
    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


      #3
      Re: DC Ceiling Fan Motor Controller / receiver

      Thanks - Apologies - I've tried hosting them differently this time;


      Comment


        #4
        Re: DC Ceiling Fan Motor Controller / receiver

        Thanks - Apologies - I've tried hosting them differently this time;





        Attached Files
        Last edited by 265chemic; 01-14-2020, 12:06 AM.

        Comment


          #5
          Re: DC Ceiling Fan Motor Controller / receiver

          You mentioned that it would work if the switch was left on for a long time. Possibly a cap going bad, or heat build-up and thermal expansion remaking a bad connection. Have you tried hitting the board with hot air?

          Comment


            #6
            Re: DC Ceiling Fan Motor Controller / receiver

            Have you tried swapping the 68uf 450v between the boards.
            Last edited by R_J; 01-14-2020, 12:58 PM.

            Comment


              #7
              Re: DC Ceiling Fan Motor Controller / receiver

              change out U2.

              Comment


                #8
                Re: DC Ceiling Fan Motor Controller / receiver

                Originally posted by will62 View Post
                You mentioned that it would work if the switch was left on for a long time. Possibly a cap going bad, or heat build-up and thermal expansion remaking a bad connection. Have you tried hitting the board with hot air?
                Thanks - I haven't tried hot air yet, though I do have a heat gun so will give it a go next time I pull it down. The controller is currently working again in the fan (after being left on for some time) but next time the switch is flipped we're back to non responsive ill bet.

                Comment


                  #9
                  Re: DC Ceiling Fan Motor Controller / receiver

                  Originally posted by R_J View Post
                  Have you tried swapping the 68uf 450v between the boards.
                  Thankyou - I haven't though the 'bad' board cap tested okay and had a good ESR. That would typically be something worth trying though would it, even if testing says okay?
                  Last edited by 265chemic; 01-15-2020, 03:08 PM.

                  Comment


                    #10
                    Re: DC Ceiling Fan Motor Controller / receiver

                    Originally posted by CapLeaker View Post
                    change out U2.
                    I've never swapped out an IC that size before, with the little pins and many contacts. What happens with the hidden contacts underneath? I assume there must be a method for doing so - what would be the typical way to tackle replacing something like that?

                    Comment


                      #11
                      Re: DC Ceiling Fan Motor Controller / receiver

                      There should be a current sense resistor (0.5Ω) between ground and the VRU,V,W pins Is it ok? If the fan does eventually run I would think the ic is ok.
                      There are only 2 reasons for the Fault output being high, you say Vcc is ok, so an over current detect must be occuring

                      Comment


                        #12
                        Re: DC Ceiling Fan Motor Controller / receiver

                        I wonder if the startup motor stalled is causing the over current to trip. I wonder what will happen if he spin the fan manually then turn on the fan.
                        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


                          #13
                          Re: DC Ceiling Fan Motor Controller / receiver

                          Originally posted by R_J View Post
                          There should be a current sense resistor (0.5Ω) between ground and the VRU,V,W pins Is it ok? If the fan does eventually run I would think the ic is ok.
                          There are only 2 reasons for the Fault output being high, you say Vcc is ok, so an over current detect must be occuring
                          I will check that out next time I pull it down


                          Originally posted by budm View Post
                          I wonder if the startup motor stalled is causing the over current to trip. I wonder what will happen if he spin the fan manually then turn on the fan.
                          I did try that - no difference observed

                          Comment


                            #14
                            Re: DC Ceiling Fan Motor Controller / receiver

                            I'd measure ohms from the FAULT pin to VSS, to see if the big IC has failed. It's only supposed to assert FAULT as long as VSS is low, under 13.5V or motor overcurrent - but that one clears when motor current is normal.
                            These IC's usually blow up when they short so I'm wondering what went open-circuit to act as the fuse.

                            Comment


                              #15
                              Re: DC Ceiling Fan Motor Controller / receiver

                              Originally posted by R_J View Post
                              There should be a current sense resistor (0.5Ω) between ground and the VRU,V,W pins Is it ok? If the fan does eventually run I would think the ic is ok.
                              There are only 2 reasons for the Fault output being high, you say Vcc is ok, so an over current detect must be occuring
                              I checked all 3 0.5ohm (R500) resistors between VRU,V,W and ground - they tested okay.


                              Originally posted by redwire View Post
                              I'd measure ohms from the FAULT pin to VSS, to see if the big IC has failed. It's only supposed to assert FAULT as long as VSS is low, under 13.5V or motor overcurrent - but that one clears when motor current is normal.
                              These IC's usually blow up when they short so I'm wondering what went open-circuit to act as the fuse.
                              Thanks - I'll check this next as well.
                              Last edited by 265chemic; 01-16-2020, 03:56 PM.

                              Comment


                                #16
                                Re: DC Ceiling Fan Motor Controller / receiver

                                You say you have another controller, does it run THIS fan properly? It looks like U4 is the driver ic (IRMCK171)? It could be that it is not providing the drive signals for the ipm. This ic operates at 3.3 volts so there must be a 3.3 volt regulator on the board, maybe U7?
                                Also what is the number on U3?
                                Last edited by R_J; 01-16-2020, 06:00 PM.

                                Comment


                                  #17
                                  Re: DC Ceiling Fan Motor Controller / receiver

                                  Originally posted by R_J View Post
                                  You say you have another controller, does it run THIS fan properly? It looks like U4 is the driver ic (IRMCK171)? It could be that it is not providing the drive signals for the ipm. This ic operates at 3.3 volts so there must be a 3.3 volt regulator on the board, maybe U7?
                                  Also what is the number on U3?
                                  Yep, the 'good' board runs the 'bad' fan just fine. One of the first things I did to make sure it was isolated to the board.

                                  U4 is a IRMCF171 - https://www.infineon.com/dgdl/Infine...53567246602737


                                  I've included a better picture too.


                                  My next steps were;



                                  - Check between VR1/2/3 pins 12,13/14,15/20,21 to VSS - there should be a .5ohm resistor(s). Make sure this/these test okay. (Marked R500.) Tested - all ok. Are R22/R23/R24.



                                  - Check between pin 8 and VSS for a 1nF cap. Test. (possibly the biggest brown SMD cap near the bridge rectifier.) Is actually C17. Measures approx 1x2mm measured w. calipers. Removed from board and tested, seemed to get 85uf/.15esr initially, then stable @ 42.4uf/.15esr. This seems way too high.



                                  - Check between pin 8(RCin) and 34(VCC) for a 2M resistor. Test. (Expect Marked 205) is actually marked 684, is 680k and measures ok. Pin 8 goes to 34(VCC) via resistor and diode D2 upstream, and also after resistor branches off into into pin 1,3 of U3, which is st electronics 393 60413 - approx 5x4mm in size. Can't find exact data sheet but likely this - SO8 package (https://cdn.badcaps-static.com/pdfs/...e33e2ff658.pdf)



                                  Extra notes;


                                  - Pin 1,3 measure 15v, which is VCC supply.

                                  - Voltage across R25 measured 14.2v closest to R25 marking, 15.4 other side

                                  - Voltage across D2 Diode neg side 14.7v, 15.4 pos side

                                  - Also measured 14.7@ pin 34

                                  Image: https://photos.app.goo.gl/UATPg78AL8CNhF1F6
                                  Last edited by 265chemic; 01-16-2020, 08:13 PM.

                                  Comment


                                    #18
                                    Re: DC Ceiling Fan Motor Controller / receiver

                                    After testing the cap I attempted to resolder it back - it escaped my tweezers, shooting off somewhere into the ether.



                                    That said, out of interest I reinstalled the controller and it worked after sitting switched on for 48 hours or so. Does this give any more certainty the cap was at fault? Is there a way I can find a replacement without having to measure one off the good board? From some research it sounds like the size plus voltage may be indicative of capacitance in general, is that right? It's from a 15v part of the circuit.

                                    Comment

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