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    Netgear R6300v2

    Hello,

    i picked this router up at the local goodwill for $4, brought it home and tested it out, seemed to work ok, so I flashed it with the recommend Kong build of dd-wrt, still working good.
    I then unplugged it to move it to another location and when I plugged it back in it was bricked. Completely unpingable.
    Tried a different power brick with similar ratings from another working router and it made no difference.
    Took the router apart and hooked up a serial connection and there was no output.
    I unplugged it for a while and then plugged it back in and it started working again. Worked great for several hours, so I thought maybe dd-wrt was causing some issue when powering off,
    so I flashed back to the stock Netgear firmware and then did a factory reset for good measure.
    Turned the router off and then back on and again bricked.
    I leave it unplugged for a while and it works again until the next time it's turned off.

    I only see 3 caps on the board. 1 330uF 16v near the power plug and 2 solid caps that I think are 470uF 6v on the opposite corner of the board.
    None of them look like they are bulging or leaking, but I know that doesn't necessarily mean that they are good.

    Does the symptoms this router is having seem like the caps are likely the problem?
    Maybe something else in the power section?

    thanks
    Attached Files

    #2
    Re: Netgear R6300v2

    anyone?

    thanks

    Comment


      #3
      Re: Netgear R6300v2

      no way to know,
      it's a try it and see type situation.

      Comment


        #4
        Re: Netgear R6300v2

        Originally posted by Gorrillasnot View Post
        I only see 3 caps on the board. 1 330uF 16v near the power plug and 2 solid caps that I think are 470uF 6v on the opposite corner of the board.
        None of them look like they are bulging or leaking, but I know that doesn't necessarily mean that they are good.
        The silver caps with purple are Sanyo SEPC - a high quality series of polymer caps, so it's unlikely those are the cause of the issues.

        Meanwhile, the brown cap show in this picture...
        https://www.badcaps.net/forum/attach...7&d=1514693903
        is made by United Chemicon - another popular good Japanese brand. That said, they did have a few series that are known to go bad and these are the KZG and KZJ. On the other hand, series like KY, KYB, KZE, KZH, and KZN are very good. So depending on which series of Chemicon you have for that cap, that may or may not be the source of issues.

        Other than that, I can't say what could be wrong with the router.
        Maybe the main chip under the heatsink has bad/weak BGA? Maybe the RAM itself is going bad? Or it's possible that even the Flash memory chip (that holds the firmware) is starting to go bad. Unfortunately, I don't have any tips on how to troubleshoot the router to test the above items. I'm hoping that someone else does, though.

        Originally posted by stj View Post
        no way to know,
        it's a try it and see type situation.
        Well, not exactly, given the cap brands.
        Last edited by momaka; 01-05-2018, 08:19 AM.

        Comment


          #5
          Re: Netgear R6300v2

          no electrolytic lasts forever if it's stressed or runs hot.
          i'v replaced loads of rubycon ZL and panasonic FC that failed.

          Comment


            #6
            Re: Netgear R6300v2

            I replaced the 330uF 16v cap with a Panasonic FM series and it made no difference.
            The router had been running for 3 days strait streaming content to a HDTV without a hiccup, then I unplugged it and replaced the cap and it is now bricked again.
            I'll keep messing with it and it will eventually come back to life.

            I hate to throw away a AC class router, but I don't know what else to try.

            If the cpu, ram, etc were bad you would think it would lock up or go flakey at any random time..I only have problems during power cycle..it would seem the problem is in the power circuit, but I dont know what it could be.

            thanks
            Last edited by Gorrillasnot; 01-06-2018, 12:16 PM.

            Comment


              #7
              Re: Netgear R6300v2

              Originally posted by Gorrillasnot View Post
              If the cpu, ram, etc were bad you would think it would lock up or go flakey at any random time..I only have problems during power cycle..it would seem the problem is in the power circuit, but I dont know what it could be.
              Well, if the problem is with solder joints (which is most likely to be with any hot-running BGA stuff like the CPU and/or RAM and large components), then you are indeed most likely to experience problems only during a cold boot.

              Try this: when the router appears bricked, use a hair dryer and heat it up well for a few minutes. Then reset and/or power-cycle the router and see if it comes back to life.

              Originally posted by stj View Post
              no electrolytic lasts forever if it's stressed or runs hot.
              i'v replaced loads of rubycon ZL and panasonic FC that failed.
              I doubt there is anything in this router that runs so hot to make those caps fail. Perhaps if this was a passive or semi-passive PSU, I'd be more likely to believe that. But good brand "bad" caps in a router? I doubt it.

              Comment


                #8
                Re: Netgear R6300v2

                this issue could be a failing flash chip - maybe the hot-air / hair-dryer trick would help track it down.

                Comment


                  #9
                  Re: Netgear R6300v2

                  I tried heating up the 2 heat sinks and the Samsung flash chip with a heat gun set on low.
                  It got pretty warm to where I couldn't touch anything with out getting burned (maybe too hot?)
                  I then tried plugging it back in and it was completely dead..no lights at all were lit.
                  I waited a couple minutes and tried again, this time the power, internet, and Netgear logo lights were all on (usually this is the lights that are lit when the router works), but it was bricked. Unplugged the router for an hour then plugged it back in and it fired right up and everything began working as it should.
                  I turned it off and then back on and of course it is bricked again.

                  Anything else I can try?

                  thanks

                  Comment


                    #10
                    Re: Netgear R6300v2

                    Was any testing done after the successful flashes? I would need to know if the unit works fine in place doing routing. If it does work, but does not survive a power-off cycle then you have a couple of difficult possibilities, NVRAM possibly faulty or possibly power-up reset circuit. At this point get the generic chip data sheet(s) and check the reset activity during power up, as well as when the unit is on. Insure that your main and sub power regulators are all present and showing correct voltages. Keep notes.
                    Is it plugged in?

                    Comment


                      #11
                      Re: Netgear R6300v2

                      Originally posted by Longbow View Post
                      Was any testing done after the successful flashes? I would need to know if the unit works fine in place doing routing. If it does work, but does not survive a power-off cycle then you have a couple of difficult possibilities, NVRAM possibly faulty or possibly power-up reset circuit. At this point get the generic chip data sheet(s) and check the reset activity during power up, as well as when the unit is on. Insure that your main and sub power regulators are all present and showing correct voltages. Keep notes.
                      The only testing I did was to make sure the router worked as a standard router/AP and as a client bridge. I've also tested the WiFi speeds (both 2.4GHz and 5Ghz) by transferring large files between two PCs.
                      Once the router is on it works great in all 3 of the firmwares I have tried (stock, dd-wrt, and tomato) for as long as I leave it on, which so far has been 3 days.

                      When you say get the data sheet(s) do you mean for the flash chip or for it, the cpu, and ram as well?
                      Flash Chip
                      How do I check the reset activity?
                      Where are the main and sub power regulators?

                      I'm still a newb and have much to learn.

                      thanks

                      Comment


                        #12
                        Re: Netgear R6300v2

                        Test it with a different power adapter.

                        Comment


                          #13
                          Re: Netgear R6300v2

                          yep that's one of the first things I tried.
                          I have had it powered on for 7 days this last time running as a client bridge for an htpc and as a test I tried power cycling it and it bricked..if it was a bad solder joint on the cpu or a bad flash chip wouldn't it cause issues while its running and not just on power up?

                          thanks

                          Comment


                            #14
                            Re: Netgear R6300v2

                            depends,
                            if the flashchip is serial (8pin) then it is copied into ram at powerup.

                            Comment


                              #15
                              Re: Netgear R6300v2

                              Take some measurements of the voltages when the router works to compare when it's faulty, maybe you have a bad voltage regulator.

                              Comment


                                #16
                                Re: Netgear R6300v2

                                seems to me a couple of years ago I had same kind of problem on that same kind of router. After years of good service, it needed to be rebooted almost on a daily bases. I think I've changed out the caps and put a different PSU on it and it is still working like a champ to date. 3 caps sounds about right.
                                Last edited by CapLeaker; 01-14-2018, 09:00 PM.

                                Comment


                                  #17
                                  Re: Netgear R6300v2

                                  Originally posted by stj View Post
                                  depends,
                                  if the flashchip is serial (8pin) then it is copied into ram at powerup.
                                  The flash chip is a Samsung K9F1G08U0D-SCB0. I think it is 48 pins.
                                  I see what you saying about loading from flash then running from ram.
                                  You would think though if the flash was bad it would always be bad and never boot.
                                  Originally posted by cpt.charlie View Post
                                  Take some measurements of the voltages when the router works to compare when it's faulty, maybe you have a bad voltage regulator.
                                  That's a good idea, but I am newb and not sure where I would need to test the voltages at and what value they should be. I only have very limited electronic experience with TVs and those are fairly easy as most values and test points are marked on the boards.
                                  Originally posted by CapLeaker View Post
                                  seems to me a couple of years ago I had same kind of problem on that same kind of router. After years of good service, it needed to be rebooted almost on a daily bases. I think I've changed out the caps and put a different PSU on it and it is still working like a champ to date. 3 caps sounds about right.
                                  In my case it's not that it needs rebooted, but the exact opposite. When I mess around with it and finally get it to boot up it will run flawlessly for however long it is powered on.
                                  If I unplug it or powercycle it with the on/off button it bricks every time.
                                  To get it to come back on I have to mess around with plugging/unplugging it while waiting 10-30min in between..sometimes it takes all day of doing this before it will come back to life.
                                  Attached is a pic..Almost 8 days uptime with 0 errors., but if I was to go turn it off and then back on it would brick.
                                  I did replaced the 330uF 16v cap near the power plug with a Panasonic Fm, but I didn't replace the solid caps on the opposite corner of the board..Should I try replacing those?

                                  thanks
                                  Attached Files
                                  Last edited by Gorrillasnot; 01-15-2018, 10:05 AM.

                                  Comment


                                    #18
                                    Re: Netgear R6300v2

                                    have you tried re-flashing it?

                                    Comment


                                      #19
                                      Re: Netgear R6300v2

                                      Originally posted by stj View Post
                                      have you tried re-flashing it?
                                      Yes. I have had Netgear stock firmware, Tomato, and dd-wrt.
                                      The problem is the same with no matter what firmware I have used.

                                      thanks

                                      Comment


                                        #20
                                        Re: Netgear R6300v2

                                        I'm not sure exaxtly where to test voltages at, but at the 330uF 16v cap, near the power plug, I get 12v when plugged in and power button off. It drops to 11.7v when power button is on while bricked and 11.6v when powered on and not bricked.

                                        These voltages seem about right?

                                        Comment

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