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  • Gpx4500 problem

    My ml gpx4500 got low depth no more 10cm . After opning it found two burnt transistor in input stage . And anothor one seems photos . I need known thers part names .
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  • #2
    What is Replacement for 2n7002f (w7f) . Did 2n7002 work fine?

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    • #3
      Can anyone help me where can I connect the anode/gathod of the diode directly because I lost track ? and I can't remove the paint
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      • #4
        you can use epoxy remover or remover for oil paint. go to building shop near you. do not say you are not able to remove the paint.

        mark all wires by color varnish. you have to keep varnishes of different colors in your home. then desolder.
        also do a photo on every your step of the desoldering.
        Attached Files

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        • #5
          Originally posted by kt315 View Post
          you can use epoxy remover or remover for oil paint. go to building shop near you. do not say you are not able to remove the paint.

          mark all wires by color varnish. you have to keep varnishes of different colors in your home. then desolder.
          also do a photo on every your step of the desoldering.
          I I don't need to remove the wires I need to reconnect the track ( between doid anod/gathod pin ) just by wire but I don't know where it can be soldered on the other end of the board

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          • #6
            [QUOTE=hooby life;297613]Can anyone help me where can I connect the anode/cathode of the diode directly because I lost track ? and I can't remove the paint
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            Why can you not remove the paint where the pad has been damaged carefully scrape the around where the pad was I use a scalpel and you should see the fine copper edge of where the pad tore off with luck you should be able to tin the torn edge and with a blob of solder get a connection to the new Diode or you will have to find where it connects to and connect it with a wire link GOOD LUCK.

            Regards, Ian.

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            • #7
              Originally posted by hooby life View Post
              I I don't need to remove the wires I need to reconnect the track ( between doid anod/gathod pin ) just by wire but I don't know where it can be soldered on the other end of the board
              There is no connection to the middle pin on the BAV99 diode on to the circuit board Pin one on BAV99 goes to pin 3 on 797 opamp and BAV99 pin 3 is ground. It will take you forever to find a track that is not on the board.

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              • #8
                Originally posted by detectormods View Post
                There is no connection to the middle pin on the BAV99 diode on to the circuit board Pin one on BAV99 goes to pin 3 on 797 opamp and BAV99 pin 3 is ground. It will take you forever to find a track that is not on the board.
                I have changed the components. Transistor K72 SMD instead of sk1334 and two PAV99. The same problem, the detector works, but it only captures large objects at a distance not exceeding 10 cm. In my country, obtaining a reagent is more difficult than obtaining a nuclear weapon, even some solutions are prohibited. In your experience, you may have encountered many of the same malfunctions with gpx devices.
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                • #9
                  Irf9630 is shorted what can use instead ?

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                  • #10
                    The IRF9630 is a common failure due to being rated only to 200 volts, use a FQP9P25 instead ,you can but from eBay, but beware fake Chinese relabeled components, it has a voltage rating of 250 volts and should not get avalanched by fast transient voltage spikes if the 200 volt capacitor starts to lose capacitance. To avoid in the field failure all detectors using IRF9630 Mosfet should replace with FQP9P25

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                    • #11
                      Originally posted by detectormods View Post
                      The IRF9630 is a common failure due to being rated only to 200 volts, use a FQP9P25 instead ,you can but from eBay, but beware fake Chinese relabeled components, it has a voltage rating of 250 volts and should not get avalanched by fast transient voltage spikes if the 200 volt capacitor starts to lose capacitance. To avoid in the field failure all detectors using IRF9630 Mosfet should replace with FQP9P25
                      Ok mr woody i found an original fsp9634 250v . Its simmillar part number only "id" is 6.5A for9630 and 9634 is 5Ampr

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                      • #12
                        By just swapping components like that you can cause further devaluation of the device down to 300$ brick. I would really suggest trying to obtain suggested parts and less experiments because the lack of circuit, the pesky white paint and the overal complexity.

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                        • #13
                          Originally posted by eclipse View Post
                          By just swapping components like that you can cause further devaluation of the device down to 300$ brick. I would really suggest trying to obtain suggested parts and less experiments because the lack of circuit, the pesky white paint and the overal complexity.
                          Why not if I can get the required things in a timely manner and easily . I allways choose simillar part suggeste .

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                          • #14
                            Their specs are similar, both available from mouser.


                            Attached Files

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                            • #15
                              Originally posted by eclipse View Post
                              Their specs are similar, both available from mouser.


                              Any way to remove paint ?

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