I've bricked and unbricked a router (TL-WR1043ND v2.1) first time in my life.

I've powered it via VCC only during unbricking and it worked fine in the end.

Then I wanted to power it with external power supply and it doesn't show any sign of life.

If I connect it to VCC again it works OK.

Nothing seems fried. It seems like something blocked external power supply after powering it via VCC.

Any ideas?

Edit: the power adapter shows 12V, so it is working.

(Last edited by Aambro on 8 Dec 2014, 02:26)

I am not familiar with that model but I assume it has a downconverter of some sort which lowers the voltage supplied by the external PS to whatever the unit accepts. If this is not true, please ignore my suggestion. Otherwise, you might check if the converter is still working and connected to the input jack.

(Last edited by aboaboit on 8 Dec 2014, 15:13)

I will post a photo of it. I have a voltmeter, but I lack knowledge of how to check if components are working.

I've been measuring some voltages across elements and they were 12V on the on-off switch, 5,2V and 1,1 on capacitors in the vicinity of jack.

Plug in the 12 volts, see if you have 3.3 volts on the VCC line.  The 8 pin chips with inductors nearby are the primary voltage regulators.  All the logic and memory chips in a router run on 3.3 volts or a lower voltage that is locally regulated down from the 3.3 volts.  The 5 volt regulator is only for the USB port.

(Last edited by mk24 on 8 Dec 2014, 16:39)

Thank you mk24. I don't have 3,3V there. I might have fried something because I was using 5V on VCC

What can I do next?

http://prntscr.com/5ekce5

(Last edited by Aambro on 8 Dec 2014, 16:54)

I must add that powering with 5V through VCC still makes the router working although now I don't know if this is still a good idea.

That's not a good idea.  You may have fried the 3.3v regulator chip by passing power through it backwards.

Can you help me identify this 3.3v regulator chip? Can I just replace it with new one?