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Crown Xti 1000 - No power

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    #21
    Re: Crown Xti 1000 - No power

    Originally posted by R_J View Post
    So now the power supply is drawing current again, but the K1 relay is not being energized to short RT6, What is the V_BULK voltage now?
    So what are the voltages on V_KSTART and +15V_CTRL
    Also are you getting +30 & -30 voltage on the transformer secondary, On C35 or C46 (measured to chassis)

    U14 should be driving the U18 gate driverthat will be driving the two fets Q28 & Q31, I would guess they are ok, They will drive HB_OUT which drives the T1 transformer, if that circuit is working you should have the secondary voltages.
    The +30 volts is required for the relay supply (via Q16) to A1, Then if the micro U1 is working it should output the SOFT_START signal to Q17 which turns on Q18 energizing K1 which will short out RT6.
    Yup I went through that soft start circuit and I found no evidence of anything short. it was a pretty thorough of lifting legs and going through a series of diode and transistor tests.

    What would a shorted K1 sound like would it sound like its sort of trying to switch on as I hear a fate noise and I doubt its rt6 making the noise.

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      #22
      Re: Crown Xti 1000 - No power

      If the switching power supply is working it will provide the run voltage via T1 (pin6) and D26. If its not working it could be due to the primary winding not being driven by the fets, Check Q26 ~ Q31 and also the gate drive resistors R347 ~ R350

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        #23
        Re: Crown Xti 1000 - No power

        K1 is a relay. It is there to bypass the RT6 thermistor once the power supply starts. It will go CLICK. and the relay contacts will close shorting RT6.
        If you look at the schematic you will see A1 and B2, they are the relay's coil, either measure the voltage across A1 & B2 (should be 24 volts if energized) or measure from ground to A1 (should be 30 volts) and then B2.
        Last edited by R_J; 08-19-2019, 10:24 PM.

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          #24
          Re: Crown Xti 1000 - No power

          I am getting voltage at D26 and its 21v to 30v

          Their a fate tapping noise. would this be k1 trying to switch on?

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            #25
            Re: Crown Xti 1000 - No power

            You would be better off checking the voltage on C45 to see if you are getting +30 volts.
            The voltage on D26 will be misleading because it is also supplied by VK_START.
            Their a fate tapping noise. would this be k1 trying to switch on?
            maybe? the way to find out is to measure the voltage on the coil.
            Last edited by R_J; 08-19-2019, 10:30 PM.

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              #26
              Re: Crown Xti 1000 - No power

              where is c45 in the schematic

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                #27
                Re: Crown Xti 1000 - No power

                Page 6, Off T1 pin17 through D13 to C45 (+30 volt secondary supply)

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                  #28
                  Re: Crown Xti 1000 - No power

                  I found it its rising to 3v then drops back.

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                    #29
                    Re: Crown Xti 1000 - No power

                    Originally posted by R_J View Post
                    You would be better off checking the voltage on C45 to see if you are getting +30 volts.
                    The voltage on D26 will be misleading because it is also supplied by VK_START.
                    maybe? the way to find out is to measure the voltage on the coil.
                    there is no voltage at that coil

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                      #30
                      Re: Crown Xti 1000 - No power

                      Check the voltage on D31, it should be 16 volts, this will allow the regulators to supply +15V_CTRL If this voltage is good (15 volts)

                      Check that there are not any shorted output transistors killing the +V1 or the -V1
                      This is the situation where is it the primary not providing the drive or is there something on the secondary that is shorted not allowing the power supply to operate (being in protection)
                      Off T1 pin 17 is LV1, (over to the right of that page) is the small circuit that drives RAIL. This RAIL signal is what the micro monitors and if the secondary voltage is where it should be, Thats when it tells the soft start relay K1 to close.
                      Last edited by R_J; 08-19-2019, 11:12 PM.

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                        #31
                        Re: Crown Xti 1000 - No power

                        Originally posted by Amraks View Post
                        there is no voltage at that coil
                        Thats because there is only 3 volts on the secondary and not 30v. Start checking for shorted output transistors

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                          #32
                          Re: Crown Xti 1000 - No power

                          which output transistors not sure where I am looking.

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                            #33
                            Re: Crown Xti 1000 - No power

                            Ok so across Q28 and Q31 collector and emitter both ways is reading 0.00v in diode mode.
                            I would say these are bad?

                            Also this board doesn't have these like in the schematic
                            r682
                            r683
                            c290

                            c299
                            r794
                            r795
                            Last edited by Amraks; 08-20-2019, 01:33 AM.

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                              #34
                              Re: Crown Xti 1000 - No power

                              confirmed Q28 and Q31 test bad out of circuit.

                              I tested them NPN and PNP transistors

                              Q26 KSC3265 NPN

                              Q27 KSA1298 PNP

                              Q29 KSC3265 NPN

                              Q30 KSA1298 PNP

                              On multimeter
                              I have tested V_BULKRTN to Q27 getting O.L
                              I have tested TP30 to Q27 getting O.L
                              Positive to T30 - Negative to V_BULKRTN getting O.L
                              Negative to T30 - Positive to V_BULKRTN getting 0.922v

                              So all along it was the IGBT's

                              Would it be safe to replace them guys?
                              Last edited by Amraks; 08-20-2019, 06:27 AM.

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                                #35
                                Re: Crown Xti 1000 - No power

                                If Q28/31 are shorted, check the gate resistors also (10Ω) if they are ok and the gate drive transistors check ok, I would try replacing q28/31.
                                I see digikey.au carriers them https://www.digikey.com.au/products/en?keywords=stgy40
                                Last edited by R_J; 08-20-2019, 08:53 AM.

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                                  #36
                                  Re: Crown Xti 1000 - No power

                                  I already have them in my shopping cart with rs.online its free shipping and next day delivery

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                                    #37
                                    Re: Crown Xti 1000 - No power

                                    Thats good, I hope thats all that is wrong.

                                    Comment


                                      #38
                                      Re: Crown Xti 1000 - No power

                                      Ill keep you posted R_J thanks for your help. that schematic wasn't easy to follow being unsearchable but I think I under stand it a bit more now.

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                                        #39
                                        Re: Crown Xti 1000 - No power

                                        Hey its been awhile since I have gotten around to doing this.

                                        I made the mistake of leaving two resistors pulled up r376 and r425
                                        I ended up blowing Q31.

                                        Q28 is fine by the looks of it.

                                        Is it fine just to replace Q31 these transistors are expensive not sure what I should be checking now.
                                        not sure if I can use a different package for testing purposes.

                                        the package it is now seems rare which is Max247
                                        https://au.rs-online.com/web/p/igbts/6868357/

                                        Just wondering I can substitute this for any same rated IGBT what characteristics am I looking for when comparing.

                                        Comment


                                          #40
                                          Re: Crown Xti 1000 - No power

                                          mouser has them lots cheaper .no idea about shipping cost https://www.mouser.co.uk/ProductDeta...f%252BTg%3D%3D

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