Some time ago there was a topic with similar name but...

In last six months I had more than 15 dead RB 450 RouterBoards. The cause of dead on all of them were the 3 or 4 leaky capacitors 500 (560?)uF, 6.3V

I have repaired them all, but not without problem.
First, there is the problem with pulling them out from the PCB, as the through holes are so tight that makes capacitor desoldering almost impossible. No need to mention that replacement capacitors are now soldered on the top side of the PCB.
Second, (and it happened in more than 80% of the cases) when the capacitors were changed RB 450 would not start with original power supply (24V). It would not start with any other power supply (no matter the voltage) so I decided to try it on regulated DC power supply just to see if it drains to much current.
Starting with 0V and raising slowly... When the voltage reached 5,8V DC router started as it should.!!!!!!

After that, I've tried again with the different power supplies and it does not work with original one but only with lower voltages (7,5 - 18V).

I would like to hear a comment from MT guys it they have similar experiences....

Cheers

Hi, with PCB holes and TH capacitors everything is ok. Your soldering-iron is not enough power. This Caps connected to ground layer and power layer and provide good heat dissipate ability. Use 45W or higher power soldering-iron to replace this caps.
Regarding your second problem description testify about too small capacitance on buck convertor output. Check is it your replacement cap have 470uF or higher capacitance and do you solder it with right polarity. Else use small awl and soldering-iron to clear PCB holes.

Remember to use low ESR capacitors. Original power supply units might not supply enough inrush current required for initial capacitor charge-up, that explains your success with higher power PSU. Also pick capacitors carefully, because these Chinese made cheap ones can't withstand high environmental temperatures and dry out eventually. I do believe the most common are 105 'C caps, which are enough. In most cases replacing capacitors is only thing required to fix the problem.. but some times more serious damage is done - blown regulators, diodes, other components.

Hello
we use many RouterBoard MikroTik RB411 for comunicaion wireless.
after about 4 month we have a problem with this RouterBoard and it was Blink LED on
RB411 and turn off turn on,
we found solution for fix this problem: xchange "capacitor 560 uf 6.3v Su'scon"

But we want to know :
1- why happen this problem?
2- there is other sulotion?
3- we use many this RouterBoard and want use next time, what we do for prevent this problem?

new routerboards no longer have this problem, this was fixed a long time ago by changing to a different part.

Ok, I very research in internet some people proposal to "Change POE and Adapter Voltage, what is your Comment?

Same problem, after changing caps, a 24v power supply won't work but a 12v power supply works fine.