What’s my problem

[hayabusa1300]

Hello I’m Kamal from Beiruit Lebanon coming here for some assistance. I have a TP-Link router that stopped working after I accidentally used a
24V 0.38A power adapter when I should of used the 12V 1.5A adapter instead. The router lights now flicker on and off and then gradually fades away. I am good with micro soldering but don’t have much knowledge in chips transistors capacitors. Can anyone tell me what likely needs replaced or how to diagnose. I do hear some static coming near one of the Capacitors each time the flickering occurs. The average monthly income here is 60$US and I can’t afford to purchase a new router for $45. I’m really upset about this honest mistake and hope someone here can help bring it back to life. My prayers go out to those who can please chime in and take some time to help me figure out what needs replacing

 

[Diver300]

Hello.

Can you get a clearer photograph of the two 8-pin ICs near the capacitors? They are the black square components with 4 silver-coloured pins one each side.

If the capacitors are making a noise, they are probably damaged. What is written on the side of them? If you are changing electrolytic capacitors, you can use larger voltage or larger capacitance. You must make sure that the capacitors are fitted the correct way round.

 

[rjenkinsgb]

Hi,
can you take more photos, especially the area in the first two pictures, but being sure to focus on the board surface and IC numbers.
Plus photos of the underside of the PCB so the traces and any other surface mount components can be seen.

The noise may be from the inductor (the square object), if the PSU is failing to run properly.

It is, unfortunately, possible that the damage has gone beyond the PSU part and the main CPU is wrecked.. Time will tell.

 

[hayabusa1300]

Yes I will upload the pictures and also a video now

 

[Diver300]

The 25 V capacitors are unlikely to have been damaged by a 24 V supply, even if it was actually at a slightly higher voltage.

Is the 24 V supply the same polarity as the 12 V one? Are + and - in the same place. There is a diode (D1) to protect against damage if the polarity is wrong, but it would be worth checking that diode.

One of the 8-pin integrated circuits is a buck regulator, an APW8720B. https://pdf1.alldatasheet.com/datasheet-pdf/view/548591/ANPEC/APW8720B.html
That is what is most likely to have been damaged, because it is only rated to 16 V.

You could try finding a replacement. You will need a hot air gun to unsolder it, because it has a metal pad under the IC and those are just about impossible to solder with a soldering iron.

You could also try providing the power from another power supply. If you can measure the resistances of R14 and R10, the output voltage can be calculated.

The output voltage will be 5 V or less, because the other electrolytic capacitors are rated at 6.3 V. However, it would not be safe to assume that it is 5 V, because it could be 3.3 V or less, and 5 V would cause damage.

When you find the voltage, if you supply power to the + and - of the 6.3 V electrolytic, the router might work.

 

[rjenkinsgb]

Check for continuity across the ends of FB1, then across FB2, both near the back of the power socket.

There is just a possibility that an overload has blown one of those; they are only noise filters and should read near zero ohms.

 

[hayabusa1300]

The 25 V capacitors are unlikely to have been damaged by a 24 V supply, even if it was actually at a slightly higher voltage.

Is the 24 V supply the same polarity as the 12 V one? Are + and - in the same place. There is a diode (D1) to protect against damage if the polarity is wrong, but it would be worth checking that diode.

One of the 8-pin integrated circuits is a buck regulator, an APW8720B. https://pdf1.alldatasheet.com/datasheet-pdf/view/548591/ANPEC/APW8720B.html
That is what is most likely to have been damaged, because it is only rated to 16 V.

You could try finding a replacement. You will need a hot air gun to unsolder it, because it has a metal pad under the IC and those are just about impossible to solder with a soldering iron.

You could also try providing the power from another power supply. If you can measure the resistances of R14 and R10, the output voltage can be calculated.
View attachment 133146

The output voltage will be 5 V or less, because the other electrolytic capacitors are rated at 6.3 V. However, it would not be safe to assume that it is 5 V, because it could be 3.3 V or less, and 5 V would cause damage.

When you find the voltage, if you supply power to the + and - of the 6.3 V electrolytic, the router might work.

Using multimeter on the beep setting and testing r14 and r10 both gives a beep and shows a reading of 0

 

[hayabusa1300]

Check for continuity across the ends of FB1, then across FB2, both near the back of the power socket.

There is just a possibility that an overload has blown one of those; they are only noise filters and should read near zero ohms.

Using a multimeter on the beep setting checking fb1 and fb2 both give a beep and show a reading of 0

 

[Diver300]

Try using the Ohms setting, if your multimeter has one.

It sounds like the APW8720B is shorted. If it is completely shorted, it would be what is making the multimeter beep.

 

[hayabusa1300]

D1 shows these values

 

[rjenkinsgb]

I think Diver300 is probably correct, the APW8720B will need replacing.