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ASUS RT-AC87U problem

Discussion in 'ASUS AC Routers & Adapters' started by redliquid, Aug 25, 2019.

  1. redliquid

    redliquid New Around Here

    Joined:
    Aug 25, 2019
    Messages:
    1
    Hello all!

    I need help with diagnosing what wrong with a router. I have ASUS RT-AC87U and something is wrong with 5Ghz WiFi. The switch seems to work fine, I haven't checked the WAN port yet. I can't reach ASUSWRT Merlin web interface, but I can reach recovery web interface. I can connect to the default ASUS SSID on 2.4GHz. 5GHz is missing.

    Here is the log file from ASUSWRT Merlin: https://pastebin.com/XYij0Z9v

    When installing ddwrt web interface seems to work (slowly, but working with some saving WiFi settings issues), but WiFi is working only on 2.4GHz. 5GHz is missing. I can connect to the 2.4Ghz default SSID (named dd-wrt) and it seems to work correctly (I can reach every website from my cell phone (router is connected to another router via cable on port 4)).

    This is the log from ddwrt starting: https://pastebin.com/5zFfmrrK

    This is the log from Quantenna: https://pastebin.com/n1G2Br10

    I've done nvram erase. I have another router without the main processor, so there is a possibility to solder some of the chips from board to board (I'm fine with BGA soldering). I already changed a RAM (next to the main processor), but that was not an issue. I'll start to replacing the other chips after rolling out all the software issues.

    Some of the info from Quantenna:
    Code:
    quantenna # brctl show
    bridge name     bridge id               STP enabled     interfaces
    br0             8000.38d547e5a494       no              eth1_0
                                                            eth1_1
                                                            wifi0
    
    quantenna # brctl showmacs br0
    port no mac addr                is local?       ageing timer
      1     01:00:5e:7f:ff:fa       no               183.07
      1     30:85:a9:45:40:1e       no                22.02
      1     38:d5:47:e5:a4:90       no               286.26
      1     38:d5:47:e5:a4:94       yes                0.00
      2     3a:d5:47:e5:a4:94       yes                0.00
      1     90:f6:52:33:3f:5a       no                29.36
    
    
    Info from the main processor:
    Code:
    [email protected]:/tmp/home/root# brctl show
    bridge name     bridge id               STP enabled     interfaces
    br0             8000.38d547e5a490       yes             vlan1
                                                            eth1
    
    [email protected]:/tmp/home/root# ifconfig -a
    aux0       Link encap:Ethernet  HWaddr 38:D5:47:E5:A4:90
               BROADCAST MULTICAST  MTU:1500  Metric:1
               RX packets:84 errors:0 dropped:0 overruns:0 frame:0
               TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
               collisions:0 txqueuelen:1000
               RX bytes:5964 (5.8 KiB)  TX bytes:0 (0.0 B)
               Interrupt:180 Base address:0x5000
    
    br0        Link encap:Ethernet  HWaddr 38:D5:47:E5:A4:90
               inet addr:192.168.0.53  Bcast:192.168.255.255  Mask:255.255.0.0
               UP BROADCAST RUNNING ALLMULTI MULTICAST  MTU:1500  Metric:1
               RX packets:10886 errors:0 dropped:0 overruns:0 frame:0
               TX packets:12696 errors:0 dropped:0 overruns:0 carrier:0
               collisions:0 txqueuelen:0
               RX bytes:556668 (543.6 KiB)  TX bytes:5750196 (5.4 MiB)
    
    br0:0      Link encap:Ethernet  HWaddr 38:D5:47:E5:A4:90
               inet addr:169.254.39.145  Bcast:169.254.39.255  Mask:255.255.255.0
               UP BROADCAST RUNNING ALLMULTI MULTICAST  MTU:1500  Metric:1
    
    eth0       Link encap:Ethernet  HWaddr 38:D5:47:E5:A4:90
               UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
               RX packets:10648 errors:0 dropped:0 overruns:0 frame:0
               TX packets:12928 errors:0 dropped:0 overruns:0 carrier:0
               collisions:0 txqueuelen:1000
               RX bytes:764386 (746.4 KiB)  TX bytes:5813972 (5.5 MiB)
               Interrupt:181 Base address:0x6000
    
    eth1       Link encap:Ethernet  HWaddr 38:D5:47:E5:A4:90
               UP BROADCAST RUNNING ALLMULTI MULTICAST  MTU:1500  Metric:1
               RX packets:0 errors:0 dropped:0 overruns:0 frame:30733
               TX packets:1441 errors:0 dropped:0 overruns:0 carrier:0
               collisions:0 txqueuelen:1000
               RX bytes:0 (0.0 B)  TX bytes:123989 (121.0 KiB)
               Interrupt:163
    
    lo         Link encap:Local Loopback
               inet addr:127.0.0.1  Mask:255.0.0.0
               UP LOOPBACK RUNNING MULTICAST  MTU:16436  Metric:1
               RX packets:179 errors:0 dropped:0 overruns:0 frame:0
               TX packets:179 errors:0 dropped:0 overruns:0 carrier:0
               collisions:0 txqueuelen:0
               RX bytes:33872 (33.0 KiB)  TX bytes:33872 (33.0 KiB)
    
    vlan1      Link encap:Ethernet  HWaddr 38:D5:47:E5:A4:90
               UP BROADCAST RUNNING ALLMULTI MULTICAST  MTU:1500  Metric:1
               RX packets:10732 errors:0 dropped:0 overruns:0 frame:0
               TX packets:12928 errors:0 dropped:0 overruns:0 carrier:0
               collisions:0 txqueuelen:0
               RX bytes:577174 (563.6 KiB)  TX bytes:5813972 (5.5 MiB)
    
    vlan2      Link encap:Ethernet  HWaddr 38:D5:47:E5:A4:90
               BROADCAST MULTICAST  MTU:1500  Metric:1
               RX packets:0 errors:0 dropped:0 overruns:0 frame:0
               TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
               collisions:0 txqueuelen:0
               RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)
    
    
    I need help with interpreting the logs above. What else can I check in the software to narrow down the issue?

    UPDATE 1:
    Changed the RAM IC next to Quantenna - no luck.

    UPDATE 2:
    I've checked power supply - it has 15V on the output. It should be 19V. I've connected the router to the 19V laboratory power supply - and WiFi (both 2.4GHz and 5GHZ) is now working fine. I've managed to start ASUSWRT Merlin. As I can see the WAN port is not working correctly - "The network cable is unplugged". WAN2 functionality works fine.

    UPDATE 3:
    This is incredible - I had two bent pins in the WAN port... both lying on the bottom of the socket. I've managed to strait them up. They are springy, so everything is fine.

    The router is fully working now. The moral from the story - always check power adapter first when strange things are happening.
     
    Last edited: Aug 25, 2019
    royarcher and Pierino like this.
  2. Grisu

    Grisu Part of the Furniture

    Joined:
    Aug 28, 2014
    Messages:
    2,302
    yes, nothing new ;)
    power adapter and HW issues are the most common failures ...