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NR90GC Nail Gun controller board repair

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    NR90GC Nail Gun controller board repair

    I am in the process of trying to repair a controller board for a Hitachi NR90GC nail gun. The gun has no mechanical reason why it won't work. So I am assuming there's an issue with the PCB.

    I've draw a schematic of the pcb by tracing/probing around the board to help try and find out why its not working.

    Firstly can you just have a look at the schematic to check if I have made any obvious mistakes.

    Secondly can you give me a clue as to what the main IC (U1) could be, as the IC only has the marking of the model number of the nail gun on it. Could it be a custom Chip? There's a few other components that I can't find info on but I can manage without that for now.

    Thanks in advance
    Attached Files

    #2
    Re: NR90GC Nail Gun controller board repair

    c10 c11 dont look too clever

    Comment


      #3
      Re: NR90GC Nail Gun controller board repair

      the trackside looks like it got wet
      why the hell does a nailgun need a microcontroller?

      Comment


        #4
        Re: NR90GC Nail Gun controller board repair

        Most likely a re-marked microcontroller (it has internal firmware), its power supply is 3.3v per 1 pin. for 7 pins. - reset.

        Comment


          #5
          Re: NR90GC Nail Gun controller board repair

          Originally posted by stj View Post
          why the hell does a nailgun need a microcontroller?
          Because it needs to know when the nail has left the gun’s guide so it does not jam would be my guess and maybe to know if the tool is jammed so it cuts power to the motor

          The battery operated rivet gun that I has a micro controller in it as well because it controls the amount of torque that it sends to the jaws of the tool and tracks the travel of the rod
          Last edited by sam_sam_sam; 01-26-2023, 07:48 PM.
          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

          Comment


            #6
            Re: NR90GC Nail Gun controller board repair

            well they are dumb shits because crystals and resonators dont like shocks - like you get with a solenoid hammer mechanism.

            check the resonator is resonating.
            (and check the soldering on it)

            Comment


              #7
              Re: NR90GC Nail Gun controller board repair

              Originally posted by sam_sam_sam View Post
              Because it needs to know when the nail has left the gun's guide so it does not jam would be my guess and maybe to know if the tool is jammed so it cuts power to the motor

              The battery operated rivet gun that I has a micro controller in it as well because it controls the amount of torque that it sends to the jaws of the tool and tracks the travel of the rod
              The nail gun doesn't have any means to sense a nail jam the only sense it has is that the firing mechanism is fully depressed so it knows its pressed against a piece of timber before it fires. Usually if there's a jam the firing mechanism will not depress.
              When I've been testing it just this doesn't seem to be working though as the controller seems to fire without sw2 being grounded.


              Originally posted by stj View Post
              well they are dumb shits because crystals and resonators dont like shocks - like you get with a solenoid hammer mechanism.

              check the resonator is resonating.
              (and check the soldering on it)
              I will test this but the whole board was encapsulated in some kind of silicone/coating that's why it possible looks like its got wet, but that's impossible due to it having the coating until I scrapped it all of.

              Comment


                #8
                Re: NR90GC Nail Gun controller board repair

                i noticed the rubber

                Comment


                  #9
                  Re: NR90GC Nail Gun controller board repair

                  looks like quite a bit of corrosion as well as the damaged chip capacitor, i would give it a thorough clean and try then , you might be lucky

                  Comment


                    #10
                    Re: NR90GC Nail Gun controller board repair

                    This is not corrosion, the board was coated with silicone sealant.

                    Comment


                      #11
                      Re: NR90GC Nail Gun controller board repair

                      Originally posted by stj View Post
                      i noticed the rubber
                      Do you know what it is they use, I was thinking of using silicone to reseal but have read silicone can be acidic so may cause corrosion.

                      Originally posted by lotas View Post
                      Most likely a re-marked microcontroller (it has internal firmware), its power supply is 3.3v per 1 pin. for 7 pins. - reset.
                      I've drawn a blank trying to find any info on this IC, no micro controllers seem to have VCC on pin 1 and GND on pin 2.

                      Comment


                        #12
                        Re: NR90GC Nail Gun controller board repair

                        Originally posted by pintglass View Post
                        Do you know what it is they use, I was thinking of using silicone to reseal but have read silicone can be acidic so may cause corrosion.
                        i use this:
                        https://www.ebay.co.uk/itm/125281546908
                        the 705 one

                        Comment


                          #13
                          Re: NR90GC Nail Gun controller board repair

                          You can see this uses high voltage capacitive discharge to the gun solenoid.
                          There is a DC-DC converter, SCR, and HV big film cap. Careful not to get zapped.
                          I would see if it's first generating HV to charge the cap.

                          Comment


                            #14
                            Re: NR90GC Nail Gun controller board repair

                            Does it have any sighs of life? are any of the led's lit? does the exhaust fan ever run. Is the fuel cell installed properly.
                            I have worked on the paslode nail guns and only had to replace broken pistons due to nails hitting something solid and breaking the piston shaft.

                            Comment


                              #15
                              Re: NR90GC Nail Gun controller board repair

                              To be honest after some testing I don't think there's anything wrong with the controller board. I originally pulled it all apart as the fan wouldn't run, which caused the board to error.

                              When I've been testing the board I've had it powered with my bench top power supply and it seems to work fine, the fan runs ok and I get a spark. So I think the issue is that the battery's are shot.
                              They do seem to charge up ok and do hold a charge, could it be that they can't provide enough power to start the fan.

                              I'm going to make up a new battery to test when I get chance.

                              Comment

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