RB411U connection problem

Hardware MikroTik hardware general
1

Hello. (Sorry, my english is basic)

I have a problem with a RB411u, two days ago i reset the configuration of the routerboard to factory defaults because we have a problem (before the system works fine 10 months), when the reset has done the rb doesn’t connect with the ethernet cable. The winbox find mikrotik but always write the same error, connection time out if i try to connect with mac.

If i plug serial cable and ethernet cable in rb start ok, and i can enter to winbox, restore the backup, and touch all the configurations, but when i unplug the serial the problem come back, i can’t connect with the winbox.

I try to format the nand and put new routeros version (with netinstall), upgrade the firmware to the last version, but it’s the same, only works with serial cable.

When i start the rb only with the ethernet cable, I can see the orange led on ethernet and the network speed is in 10 Mbps (no access to winbox, explorer…). When i start with both cables, i can see the green led and the speed is in 100Mbps and all works fine.

The last thing i see, if i start the routerboard with a ethernet cable in a switch, the rb doesn’t start correctly, with or without the serial cable, the orange led is always on, and not connect to winbox.

I’m crazy with this problem. One idea open my mind.

Thanks.

2

I have a problem with a RB411u, two days ago i reset the configuration of the routerboard to factory defaults because we have a problem (before the system works fine 10 months), when the reset has done the rb doesn’t connect with the ethernet cable. The winbox find mikrotik but always write the same error, connection time out if i try to connect with mac.

Use IP Winbox instead of it, IP should be more stable and try SSH/Telnet too.
If they are not working, it sounds for me as hardware problem. What about the case, when serial cable is attached to RB411U (but it is not attached to second device), does RB411U load RouterOS correctly?

3

No, it doesn’t work with the serial pluged only in the routerboard. But i see that if i unplug the ethernet cable of the router, and connect it in the first beep of mikrotik start it works fine (but only the green led is on) but always with the serial cable connected.