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    Autohelm 3000

    So I have one of these on the bench for a customer, its the older analogue compass rose version. reported problem with drive motor output. a brief examination shows a defective medium power PNP power transistor which I am having trouble identifying I dont appear able to source the service manual or circuit diagram for this. Pictures below best current guess is they are a pair of BD438

    There are two BD 441
    and two of these query BD438

    Many thanks in advance

    I can produce higher res images if this will help
    Attached Files

    #2
    Re: Autohelm 3000

    complement of BD441 is BD442

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      #3
      Re: Autohelm 3000

      Not sure what you are after? both data sheets are available.
      onseni list BD441 and BD442 80v 4amp NPN & PNP
      Last edited by R_J; 06-14-2018, 12:35 PM.

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        #4
        Re: Autohelm 3000

        I have both data sheets, what I am after is input on the device that I am having trouble identifying, Complementary types are BD437 and BD441 although that looks to be a 4 with a possible 3 followed by what appears to be an 8

        This is the data sheet I was working to which lists several options,
        Attached Files

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          #5
          Re: Autohelm 3000

          The bd438 is rated 45 volts, I would use the BD442 rated at 80 volts, likely about the same price. I would use the higher voltage ones of the npn and the pnp
          or the NPN I would use the BD441
          Last edited by R_J; 06-14-2018, 04:13 PM.

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            #6
            Re: Autohelm 3000

            i would make sure what they are driving is not binding too - incase it's causing extra load.

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              #7
              Re: Autohelm 3000

              I have the drive unit here on the bench for disassembly and overhaul, so on the matter of the errant device a is a BD441 and BD442 combo going to work here given that I am not entirely sure of the device (BD438 being my best guest) and general lack of service manual / or circuit diagrams being available. In the mean time I have gone ahead and ordered the parts, will have to go with best option when they turn up lol.
              Last edited by llonen; 06-14-2018, 06:01 PM.

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                #8
                Re: Autohelm 3000

                are they dead - the mystery parts i mean.

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                  #9
                  Re: Autohelm 3000

                  They certainly are, well one definitively is one of the junctions is open cct as measured off the board the other I am not quite so sure about was getting odd readings in cct it does seem serviceable when removed. I am not entirely sure though. If I get time I might obtain a cheap transistor tester and see what that makes of it as I currently test with a fluke in semiconductor mode.

                  Comment


                    #10
                    Re: Autohelm 3000

                    Thanking everyone for their input on this repair, so after tracing out the circuit diagram for the board and confirming that the devices were configured as complimentary pairing final device choice came down to bd 442 as per above recommendation and datasheet. Drive mechanism was stripped down was indecently tested on a current limited bench supply cleaned re greased assembled.

                    Complete system then tested on a current limited bench supply, and successful results.

                    Thank you again for your input.

                    Comment


                      #11
                      Re: Autohelm 3000

                      Very nice to hear that you got it running again
                      Good job
                      9 PC LCD Monitor
                      6 LCD Flat Screen TV
                      30 Desk Top Switching Power Supply
                      10 Battery Charger Switching Power Supply for Power Tool
                      6 18v Lithium Battery Power Boards for Tool Battery Packs
                      1 XBox 360 Switching Power Supply and M Board
                      25 Servo Drives 220/460 3 Phase
                      6 De-soldering Station Switching Power Supply 1 Power Supply
                      1 Dell Mother Board
                      15 Computer Power Supply
                      1 HP Printer Supply & Control Board * lighting finished it *


                      These two repairs where found with a ESR meter...> Temp at 50*F then at 90*F the ESR reading more than 10%

                      1 Over Head Crane Current Sensing Board ( VFD Failure Five Years Later )
                      2 Hem Saw Computer Stack Board

                      All of these had CAPs POOF
                      All of the mosfet that are taken out by bad caps

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