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R8300 hardware issues (Bad Capacitors)

UmarFida
Aspirant

R8300 hardware issues (Bad Capacitors)

I have Netgear Nighthawk x8 (R8300) router which is not accepting any version of it stock firmware via serial recovery. I was able to flash it with DD-WRT and the unit is working with only 2.4 GHz radio. its not showing any 5 GHZ radio. although in ddwrt web gui it say radio is ON but its not transmitting. Later i came to know that there are a number of units that were identified having a bad capacitors. so i open it and found that its true. i need to change capacitors. But the Problem is all the capacitors are SMD type which means no values are written on them. I need a PCB layout of the motherboard to know the capacitors values. anyone knows were to look for it. router was made in vietnam 

Model: R8300|Nighthawk X8 AC5000 Smart WiFi Router
Message 1 of 8
Johnny12345
Aspirant

Re: R8300 hardware issues (Bad Capacitors)

 

UmarFida, I have the same issue about this router, did you managed to find the PCB layout and change the capacitors? Kindly share the solution if you have, thank you.
Model: R8300|Nighthawk X8 AC5000 Smart WiFi Router
Message 2 of 8
William10a
Master

Re: R8300 hardware issues (Bad Capacitors)

Sounds like you need a service manual for the router I had not seen one put out for a router unless someone release it on the side. I would believe that that could be the cause of  some of the other issues routers are having. The voltage could figure out by a volt meter if the cap is used as a filter cap for the power supply since the normal power supply is 12 volts upto 28 depending on the router I would replace it with a 50 volt cap if possible. Most other coupling caps may be around the 1uf to maybe 10uf range. The smaller value caps used for the rf circuits and decoupling stages are hard to say what they could be.

Message 3 of 8
UmarFida
Aspirant

Re: R8300 hardware issues (Bad Capacitors)

No i did not find it yet. i believe that a PCB schematic will only come from netgear engineering side. From my own router I found that Power supply filter capacitor was not there. so I put 25V 470 uf cap for SMD caps i removed some and checked individually they are all OK. in the end conclusion is board is somewhere short to ground and its not possible for me to find where the short is.

 one thing i dont understand is why the router will not boot with stock firmware but it will boot with dd-wrt. 

Message 4 of 8
William10a
Master

Re: R8300 hardware issues (Bad Capacitors)

Caps stopping Netgear's firmware from working strange you think that third party firmware would use the same pathways to talk the chip set.

Unless some of the decoupling or data bus caps have shorted out that could possible change how a program reacts. Netgear's firmware could see a bad data pathway as a reason to stop booting, never tryed to make netgear stop working by shorting out its caps before and not sure I would do now.

Message 5 of 8
antinode
Guru

Re: R8300 hardware issues (Bad Capacitors)

> [...] i came to know that there are a number of units that were
> identified having a bad capacitors. so i open it and found that its
> true.

   How, exactly, did you "[come] to know" about this capacitor problem?
How, exactly, did you "[find] that it[']s true"?

> [...] in the end conclusion is board is somewhere short to ground
> [...]

   If there is a hardware problem, then guessing at possible defects
seems (to me) to be an unlikely way to find it.

> [...] one thing i dont understand is why the router will not boot with
> stock firmware but it will boot with dd-wrt.

   Knowing what the actual problem is might clarify that mystery.  I
wouldn't expect uninformed guesswork (which is all that I could offer)
to help much.

Message 6 of 8
Johnny12345
Aspirant

Re: R8300 hardware issues (Bad Capacitors)

Thanks for all your input, I tried use Peter11742's solution to flash the initial firmware but stuck at the CFE>, I do " nvram erase" and returned with ***command=0, then I type tftpd but stuck at reading::, I don't know how long I have to wait for this reading:: process to complete so I reboot the router, few times tried but same result....

 

I searched many threads for this boot loop issue on R8500 and R8300, most of the solution is RMA, unfortunately my router was out of Warranty.

 

I found some threads about other routers which with Broadcomme SOC, maybe the root cause is during the upadating the newer firmware, the environment of the router was changed, like Internet interupped, power off, etc. Even your modem(not R8500/R8300) is DHCP pools enabled but during the  updating firmware, different IP address was assigned to R8500/R8300, these may casued the routers keep looking for the previouse configuration and finally caused bad sector on the NAND Flash, for this special R8500/R8300, they will keep boot loop until they find the previouse configuration.

 

I would suggest all netgear routers usere to restore to factory settings and download the firmware to your computer (that means local files) then manually update the firmware.

 

For this expensive toy, I have nothing to say about the engineers who develop the firmware and the lousy process caused so many users suffered.

For the bad capacitors, I am really no idea where these capacitors are and no clue how to identify them, hope you guys can give me a clue.

 

Message 7 of 8
Johnny12345
Aspirant

Re: R8300 hardware issues (Bad Capacitors)

Continue from last post...

 

I will try to ask some China Dev to flash a new nand flash for me the I will replace the bad Nand flash on the R8300, but what I know is to falsh the NEW NAND FLASH need some kind of information of the old routers, include CFE, MTD01 -08 partitions, etc... I don't know how to get this, I only can get into CFE>, when I was TTL connected to the router. SO appreciate you can enlighten me how to do it?

 

Thanks

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