Verus 325 blown charger circuit

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  • John Lansford
    Junior Member
    • Nov 2014
    • 16

    Verus 325 blown charger circuit

    I blew the charging circuit on my Verus Wireless EMS325 unit and need to know the type of chip I destroyed.

    RV1 which I believe is a Varistor.

    I know what the BG5100 chip is.

    Any help would be appreciated.
    Attached Files
  • John Lansford
    Junior Member
    • Nov 2014
    • 16

    #2
    Anyone know of available schematics?

    Thinking varistor but not sure of voltage limits.
    Does it protect oscilloscope inputs at 75-85 volts or is it power supply for oscilloscope 12 volts?

    HELP !!!!

    :-)))

    Comment

    • Witsend
      Banned
      • Nov 2012
      • 2942

      #3
      I wouldn't hold my breath with getting any sort of a detailed board diagram from here. I wonder if the identifying markings would be on the underside of the burnt chip?

      Comment

      • John Lansford
        Junior Member
        • Nov 2014
        • 16

        #4
        I removed chip and checked under microscope no markings.
        Too damaged to test with equipment.
        I have had this unit for 3-4 years I asked on this site because it is Snap-On site. Thought maybe a service tech might have schematics and be able to read through parts list.

        Worth a try.

        Thanks for your reply

        Comment

        • tech25
          Senior Member
          • Oct 2017
          • 172

          #5
          dont know what exactly is the problem, sorry, I would suggest calling Technical help and see what they can do. I attached the info if you want to read up on it,

          heres a snap shot of some of the services.
          Attached Files

          Comment

          • John Lansford
            Junior Member
            • Nov 2014
            • 16

            #6
            Received all my diodes and a TVS today.

            After replacing the parts the charging circuit is working!
            XP is working, oscilloscope working. Software all functional.
            Charged battery completely, reset time (Got that call Customer Support Dialog box) and everything working again.

            Thanks for the help.

            Actually I fix Tektronix scopes from the 60-90's as a hobby.
            But I almost always have schematics.

            This unit uses all SMD parts and WOW!! are they small, all soldering done through microscope on those blown diodes.

            Comment

            • Witsend
              Banned
              • Nov 2012
              • 2942

              #7
              dont know what exactly is the problem, sorry, I would suggest calling Technical help and see what they can do. I attached the info if you want to read up on it,

              heres a snap shot of some of the services.


              That's a handy chart But Think he's got an older unsupported wireless model you can no longer send out for repairs called a S.O.L.VERUS


              fter replacing the parts the charging circuit is working!
              XP is working, oscilloscope working. Software all functional.
              Charged battery completely, reset time (Got that call Customer Support Dialog box) and everything working again.

              Thanks for the help.

              Actually I fix Tektronix scopes from the 60-90's as a hobby.
              But I almost always have schematics.

              This unit uses all SMD parts and WOW!! are they small, all soldering done through microscope on those blown diodes.
              Reply With Quote
              Awesome, glad it worked out. Maybe you could provide the information about exactly what is the part # of what it is that's burnt out in the photo that you replaced that you might be able to source from Digi-Key, (since radio shack is no longer around) that might help someone less tech savvy to get er done.
              Last edited by Witsend; 08-15-2018, 07:44 PM.

              Comment

              • John Lansford
                Junior Member
                • Nov 2014
                • 16

                #8
                Yes, I will work on a list of parts.

                The entire path blew from my shorting the Verus through the charger circuit.
                I attached 1X probes to a floating ground Switch Mode Power Supply circuit.

                Just a brain fart on my part, as I know the rule for connecting to floating power supplies, but seeing the Low Battery Dialog box!! I plugged in the charger !! Creating the ground path exceeding the Verus voltage limits.

                But I have to say the Verus designers used excellent protection circuits.
                Parts cracked and pads vaporized but the computer, hard drive and oscilloscope circuitry survived.
                If not that unit would b e a S.O.L.brick as posters have stated.

                Good work designers,

                Comment

                • GypsyR
                  Senior Member
                  • Jul 2017
                  • 287

                  #9
                  Not being that good of an electronics tech, I have to ask. What is " the rule for connecting to floating power supplies" exactly?

                  I feel like I have probably unknowingly run up against it a time or two.

                  Comment

                  • Witsend
                    Banned
                    • Nov 2012
                    • 2942

                    #10
                    Scare-us Verus

                    I don't think you ever want to actually be charging the Scanner running the scope module off the battery of the same vehicle you are testing things on .

                    Comment

                    • John Lansford
                      Junior Member
                      • Nov 2014
                      • 16

                      #11
                      You have to connect the oscilloscope to an isolation transformer.

                      Some circuits have floating grounds ( meaning a ground voltage that is not zero and not in any way connected to earth ground. The metal case or the third prong).

                      I grounded my circuit through the battery chargers ground connection.

                      Making Earth the ground point, subjected my Verus probe 300 volts above zero.

                      BOOM!!

                      Just a dumb mistake.

                      I picked the Verus because it was floating ( Like any battery powered Digital Multimeter as an example the Fluke 87V.

                      And then I made it non-floating by plugging in the charger.

                      Comment

                      • kirkbarrow.garage
                        Senior Member
                        • Jan 2015
                        • 149

                        #12
                        Originally posted by John Lansford
                        You have to connect the oscilloscope to an isolation transformer.

                        Some circuits have floating grounds ( meaning a ground voltage that is not zero and not in any way connected to earth ground. The metal case or the third prong).

                        I grounded my circuit through the battery chargers ground connection.

                        Making Earth the ground point, subjected my Verus probe 300 volts above zero.

                        BOOM!!

                        Just a dumb mistake.

                        I picked the Verus because it was floating ( Like any battery powered Digital Multimeter as an example the Fluke 87V.

                        And then I made it non-floating by plugging in the charger.


                        I did the exact same thing with two televisions,

                        Had my main tv Bang & Olufsen on, and had repaired another one and took the aerial out of the B&O and connected to the repaired and then switched on and bang, one blown RCB and B&O tv too.

                        Not good at any time.

                        Comment

                        • John Lansford
                          Junior Member
                          • Nov 2014
                          • 16

                          #13
                          The bad parts circled: SOT-23 PIC

                          2- BAS4004E632 Shottky 40V 0.12 Automotive 3 Pin SOT-3

                          The bad parts are circled: INPUT Damage PIC

                          MBRD5H100T4g SHOTTKY DIODE 100v 5a 3-PIN DPAK
                          DIODE TVS Single UNI-Directional 23.1V 1500Watt 2 PIN SMC
                          MLC VARISTOR 42VAC/60VDC 250A 75V 2210 SMD


                          Special Thanks to one of your members ( and youtube poster) for helping me with the SOT-23 Diodes part numbers.
                          He was kind enough to take a picture of his board.
                          Attached Files
                          Last edited by John Lansford; 08-18-2018, 05:09 AM. Reason: added comment

                          Comment

                          • Witsend
                            Banned
                            • Nov 2012
                            • 2942

                            #14
                            Wow those 2 circled charred SOT-23s must of had a flame and smoke shooting out. Kinda looks like Charlie Brown wearing welding glasses. I think if the electronic board belonged to any device other than a Snap On Verus, it be set out on the curb

                            Comment

                            • John Lansford
                              Junior Member
                              • Nov 2014
                              • 16

                              #15
                              Yes,
                              It vaporized the pads under those SOT-23 parts and just so you know those parts are only about 3mm across. Yikes, they are small!

                              I made new pads out of the leg of an 8 pin DIP IC.

                              Comment

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