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    Help identifying a component on a wireless router.

    Hi,

    We have a broken Netgear wndr3400v2 dual-band wireless router. The wifi doesn't work correctly. We can see the wireless networks, however, every time we try to connect via the 2.4GHz bandwidth (for example, using wireless G), we can never access the internet / router. The router sees the device's MAC address but never assigns an IP address. If we try using a static IP address, it doesn't work. Wired works. I believe the 5 GHz band works but haven't checked.

    Anyway, I have taken it apart and identified a component that I think might be bad. It appears kind of burnt, I'm having trouble identifying it though. It's next to the button that allows us to turn the wifi on/off. It's labeled on the board as U40. The device has printed on it, DF-J16. Here's some pictures. The front of the whole board was hard to get a good pic of. I can upload multiple pics in sections of the front if needed.

    Can someone help me identify it please so I can try and find a datasheet for it? I was thinking it might be a BCW68F, package SOT-23 (we measured length and width of the chip and it seems to match the SOT-23 package size measurements).
    Attached Files
    -- Law of Expanding Memory: Applications Will Also Expand Until RAM Is Full

    #2
    Re: Help identifying a component on a wireless router.

    Before you do any hardware changes, see if your firmware is the latest and greatest from the manufacturer.

    I also see that Netgear can run openwrt.

    http://wiki.openwrt.org/toh/start?da...*~%5D=wndr3400

    You might either or the above?
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      #3
      Re: Help identifying a component on a wireless router.

      Seems to me it is being used as a switch to turn on power to 1138 coil. It is hard to tell being I can see the whole circuit clearly going to this coil. It is partially a guess.

      Comment


        #4
        Re: Help identifying a component on a wireless router.

        That Netgear router can run DD-WRT and Tomato as well.

        Comment


          #5
          Re: Help identifying a component on a wireless router.

          I also found this on the internet. Do not know how good it is. Also, make sure if you are handling components that you have a ground strap which is connected to good ground.

          http://www.stevejenkins.com/blog/201...-dd-wrt-flash/

          Comment


            #6
            Re: Help identifying a component on a wireless router.

            Concerning flashing DD-WRT if a person researches and follows ALL the instructions there will be no router bricking to worry about. For this particular router I believe it is a two part flash, you find and flash the basic DD-WRT release for the base router model type and then flash to an updated release for that specific model and v#.

            Comment


              #7
              Re: Help identifying a component on a wireless router.

              Originally posted by SteveNielsen View Post
              That Netgear router can run DD-WRT and Tomato as well.
              I did not mention DD-WRT only because it hasn't been updated since 2013-04-23. With Tomato, it has not been updated since 2010 June 28. So both are basically abandoned projects for general public usage.

              Openwrt has recent and ongoing releases which is important for security fixes. The latest release candidate was dated July 15, 2015.

              PS. My wifi router is a Linksys at home running stock Linksys firmware. While I do have a newer wifi router that can run the latest openwrt, I will use this Linksys until it dies. And yes, I have locked down the Linksys router down as best as I reasonably can.
              Last edited by retiredcaps; 09-05-2015, 05:09 PM.
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                #8
                Re: Help identifying a component on a wireless router.

                Originally posted by retiredcaps View Post
                Before you do any hardware changes, see if your firmware is the latest and greatest from the manufacturer.

                I also see that Netgear can run openwrt.

                http://wiki.openwrt.org/toh/start?da...*~%5D=wndr3400

                You might either or the above?
                Sorry for the late reply. I've been a bit busy today, running around like a chicken with my head off! Anyway, I should of explained what I did for trouble shooting first.

                First, I checked for a firmware update, there was none, according to Netgear's website. The router is using V1.0.0.38_1.0.61, the latest download I could find on Netgear's site V1.0.0.38_1.0.61.

                I did a 30-30-30 reset. When the unit was plugged in, I held down the reset button for 30 seconds. I had someone unplug it after that, kept holding it down for 30 more seconds, had them plug it back in for 30 seconds. This did a factory reset. It brought everything back to the same way it was when it was bought. I then turned the wifi on, using the button on the back, and saw the default SSID. I tried connecting with the default password that was listed on the router, it failed.

                I tried connecting via wired, after the recovery, I made sure WIFI was enabled, I disabled the 5GHz bandwidth and changed the SSID and password. I tried connecting again, same as before.

                I made sure all antennas where hooked up. It's weird because I can see it with full strength. I just cannot connect wirelessly. Before, I could with no problems. Then one day, it just stopped working. I retired the unit until I had time to work on it (which was supposed to be today). When I ripped it apart, the only thing I could see wrong with the board was that little chip by the button that turns the WIFI on/off. It appeared..I dunno, kinda burntish.

                There are pins for a serial connection, J41. It's 6 pins but the pinout is available on the net. From my understanding though, the only alternative firmware I could use would provide ethernet, not wireless, because of this unit being rev 2. I had read this on the same site you linked to earlier in the day (I had a similar idea as you did)

                WARNING: current trunk version boots but has no WiFi and no Ethernet
                Serial console required!

                From reading, the brcmfmac and brcmsmac or whatever it's called will never support this chip because it doesn't have the memory that other chips have or something weird like that. Am I misunderstanding something? Thanks!
                -- Law of Expanding Memory: Applications Will Also Expand Until RAM Is Full

                Comment


                  #9
                  Re: Help identifying a component on a wireless router.

                  Originally posted by SteveNielsen View Post
                  That Netgear router can run DD-WRT and Tomato as well.
                  Are you sure? According to their site (I checked DD-WRT as well earlier), they need a board donation for rev 2. It's listed in their database as a "WIP".
                  -- Law of Expanding Memory: Applications Will Also Expand Until RAM Is Full

                  Comment


                    #10
                    Re: Help identifying a component on a wireless router.

                    Originally posted by retiredcaps View Post
                    I did not mention DD-WRT only because it hasn't been updated since 2013-04-23. With Tomato, it has not been updated since 2010 June 28. So both are basically abandoned projects for general public usage.

                    Openwrt has recent and ongoing releases which is important for security fixes. The latest release candidate was dated July 15, 2015.

                    PS. My wifi router is a Linksys at home running stock Linksys firmware. While I do have a newer wifi router that can run the latest openwrt, I will use this Linksys until it dies. And yes, I have locked down the Linksys router down as best as I reasonably can.
                    It's nice to know this information. I've always had (and used) a really old wireless G Linksys that couldn't handle any of the other firmwares. This newer one was given to me by my sister. She was having problems with the wifi dropping constantly she said.

                    Have you used Openwrt before? I'd love to try it. I've always wanted to run a custom firmware on my router...
                    -- Law of Expanding Memory: Applications Will Also Expand Until RAM Is Full

                    Comment


                      #11
                      Re: Help identifying a component on a wireless router.

                      Originally posted by keeney123 View Post
                      Seems to me it is being used as a switch to turn on power to 1138 coil. It is hard to tell being I can see the whole circuit clearly going to this coil. It is partially a guess.
                      Come tomorrow, I'll try to get nicer pictures. I appreciate it. Do you know what kind of component it might be? I was thinking perhaps a transistor of some sort? I couldn't find any service manuals for the router.
                      -- Law of Expanding Memory: Applications Will Also Expand Until RAM Is Full

                      Comment


                        #12
                        Re: Help identifying a component on a wireless router.

                        Originally posted by Spork Schivago View Post
                        From my understanding though, the only alternative firmware I could use would provide ethernet, not wireless, because of this unit being rev 2. I had read this on the same site you linked to earlier in the day (I had a similar idea as you did)

                        WARNING: current trunk version boots but has no WiFi and no Ethernet
                        Serial console required!
                        In my search, I only searched for wndr3400 and left out v2. So when I saw v1 and v2 as listed supported, I did not go any further to research/read the caveats, etc. Since I don't have this router, I had no reason to.

                        You might want to look at the latest release candidate and scan the release notes or changes to see if your router is now supported.
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                          #13
                          Re: Help identifying a component on a wireless router.

                          Originally posted by Spork Schivago View Post
                          Have you used Openwrt before?
                          Yes, I used 14.07 and then updated 15.05 rc1 or rc2. It worked well, no problems, but then I put my old Linksys back into production. The Openwrt router is a backup.

                          People on kijiji sometime sells newer Linksys routers capable of running openwrt for $5 CDN. I look at the Linksys specs and try to get one with the most amount of flash and DRAM memory so it will likely run openwrt in the future as openwrt, like all software, grows in size.
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                            #14
                            Re: Help identifying a component on a wireless router.

                            I can do that. However, I went a bit of a different route and I doubt that it will be supported. I looked a the four drivers they used and I researched all of them and that chip. It's a weird chip, the BCM43236. Normally, the drivers load firmware onto the chip. Because this chip doesn't have any memory, they just cannot work. One of the mailing lists went a bit into detail about this. From what I gathered (and I might be wrong), one of the drivers works in tangent with another one and even if they changed their code to support this revision, it would still never work because the other one would never be able to load firmware onto the chip. They said something about Broadcom uses some proprietary way to do something funky with it. I don't know if this is true or not. I might of misunderstood.

                            Does trunk mean latest version? If not, I'll start looking at release candidates.

                            I also read this Rev 2 router is a bit tricky. If I can get firmware to load, I'll need to use TFTP to undo it to bring it back to factory (if I want wifi working). But the article said I'd need to connect via serial to enable the wired ethernet ports. Thanks for all the help and suggestions.

                            Could you suggest a good router that supports OpenWRT? I was thinking something that supported Wireless AC and gigabit ethernet ports. I don't really care about USB ports, I can't really see myself using them ever. I'd like concurrent dual-band if I could get it. Might just be time to spend some cash and get something I wouldn't need to replace for a long time.
                            -- Law of Expanding Memory: Applications Will Also Expand Until RAM Is Full

                            Comment


                              #15
                              Re: Help identifying a component on a wireless router.

                              Originally posted by Spork Schivago View Post
                              I can do that. However, I went a bit of a different route and I doubt that it will be supported. I looked a the four drivers they used and I researched all of them and that chip. It's a weird chip, the BCM43236. Normally, the drivers load firmware onto the chip. Because this chip doesn't have any memory, they just cannot work. One of the mailing lists went a bit into detail about this. From what I gathered (and I might be wrong), one of the drivers works in tangent with another one and even if they changed their code to support this revision, it would still never work because the other one would never be able to load firmware onto the chip. They said something about Broadcom uses some proprietary way to do something funky with it. I don't know if this is true or not. I might of misunderstood.
                              that's bullshit, i'v read it before with the DG824GT and seen custom firmware running.
                              the problem is the WRT people dont want to include anybody's binary blobs in the code release

                              Comment


                                #16
                                Re: Help identifying a component on a wireless router.

                                Originally posted by Spork Schivago View Post
                                Could you suggest a good router that supports OpenWRT? I was thinking something that supported Wireless AC and gigabit ethernet ports.
                                Sorry, can't help with a recommendation since my ISP connection is only 5Mbps so 802.11g is more than enough for me. I get hand me down wifi routers from friends who feel they must have the latest wifi speeds.

                                I can only suggest you get as much DRAM and flash as you can inside the router. Try to stick to a big name brand as it is likely to be supported and look at teardowns to see if the chipsets come from vendors that are open source friendly.
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                                  #17
                                  Re: Help identifying a component on a wireless router.

                                  Originally posted by Spork Schivago View Post
                                  Come tomorrow, I'll try to get nicer pictures. I appreciate it. Do you know what kind of component it might be? I was thinking perhaps a transistor of some sort? I couldn't find any service manuals for the router.
                                  I would think in this day and age it is a Cmos transistor. I would think you could check it out with a multi-meter. By connecting one of the meter leads to IC ground and they measure the voltage on the 3 leads, with the button of the wi-fi enabled and then disabled. Then if you look at it as a switch I would think two of the points will connect together while the other enables them when the wi-fi is enabled. This maybe a temporary pulse that triggers a latch. So once the latch is trigger high or low depending one the design the microcontroller or microprocessor reads it and runs a go to routine.
                                  Last edited by keeney123; 09-05-2015, 07:23 PM.

                                  Comment


                                    #18
                                    Re: Help identifying a component on a wireless router.

                                    Originally posted by stj View Post
                                    that's bullshit, i'v read it before with the DG824GT and seen custom firmware running.
                                    the problem is the WRT people dont want to include anybody's binary blobs in the code release
                                    That could of been the reason, I kind of just glanced over it. It might of been one of those, because this is a fully open source project and this chip requires a binary file, we cannot include it.
                                    -- Law of Expanding Memory: Applications Will Also Expand Until RAM Is Full

                                    Comment


                                      #19
                                      Re: Help identifying a component on a wireless router.

                                      Originally posted by retiredcaps View Post
                                      Sorry, can't help with a recommendation since my ISP connection is only 5Mbps so 802.11g is more than enough for me. I get hand me down wifi routers from friends who feel they must have the latest wifi speeds.

                                      I can only suggest you get as much DRAM and flash as you can inside the router. Try to stick to a big name brand as it is likely to be supported and look at teardowns to see if the chipsets come from vendors that are open source friendly.
                                      Okay, will do. I was thinking maybe I should look into Cisco. I know they're a bit pricey but it'd be nice to play around with a Cisco router again. Kinda miss that stuff. Last time I checked though, their wifi models where going for around 800$ (just a basic wifi model, nothing fancy). Having a lot of DRAM and flash make sense. We can only get around 50Mbps (it might be 100Mbps now) but we do a good deal of transfers between PCs using ethernet. If I had something like AC, I could maybe do them wirelessly, which would be a big plus.
                                      -- Law of Expanding Memory: Applications Will Also Expand Until RAM Is Full

                                      Comment


                                        #20
                                        Re: Help identifying a component on a wireless router.

                                        Originally posted by keeney123 View Post
                                        I would think in this day and age it is a Cmos transistor. I would think you could check it out with a multi-meter. By connecting one of the meter leads to IC ground and they measure the voltage on the 3 leads, with the button of the wi-fi enabled and then disabled. Then if you look at it as a switch I would think two of the points will connect together while the other enables them when the wi-fi is enabled. This maybe a temporary pulse that triggers a latch. So once the latch is trigger high or low depending one the design the microcontroller or microprocessor reads it and runs a go to routine.
                                        Okay, thank you. Tomorrow I'll give it a shot (I don't have access to the router right now). Thanks!!
                                        -- Law of Expanding Memory: Applications Will Also Expand Until RAM Is Full

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