Region : Greece

Model : TL-MR3420

Hardware Version : V2

Firmware Version : 3.14.9 Build 140319 Rel.38485n

ISP : OTE Telecoms

Good evening!


I came a across a very strange issue yesterday and haven't being able to fix it. I am using the router as a dsl gateway with a 3g carrier for backup, everything were going perfect for a week (switching to 3g when dsl was down, wireless, port forwarding etc), but since yesterday the router hasn't being able to use the 3g usb (E1750), i thought the usb modem hanged so i removed, it and re insert it , to my surprise i saw the status displaying "Unplugged", i restarted the modem but still nothing i tried another usb modem but still the
same, so i thought i change the SIM, so i did and i got "Identify successfully", all good but here is the problem im trying to insert the new pin for the SIM card and the message keeps saying "PIN protection is enabled. Please input PIN code." and does nothing i even tried a wrong pin to test it and i still got the same message, i also tried a third usb modem with the same results. I also tried the following:


Factory reset with backup restore
Factory reset with configuration from scratch
Left the Router without power for 30 minutes to completely discharge it self.

Is there any chance the router itself is defective ? Any help would be much appreciated since the machine is used on a production environment.

PS: I use custom apn for the carrier, also in the system log it says USB modem ok.

Regards