# Can you solve this

#### Kamal1300

Joined Aug 14, 2021
8
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

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#### Kamal1300

Joined Aug 14, 2021
8
More photos. I will be honest the only knowledge I have was de soldering and re soldering reprogramming 8 leg EEPROM chips from SRS airbag modules back few years ago. So I don’t know much else about electronics

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#### dcbingaman

Joined Jun 30, 2021
476
I was able to identify one part so far on the board. It is a buck regulator. Attached is the datasheet. If you applied 24V it might have taken out this chip. The voltage rating on the input is 5-12V. Please note the pinout:

Apply the correct 12V to the circuit. I think you should observe 12V from pin 5 to pin 3. Then look at the phase pin output Nearby should be a coil and capacitor connected to this pin per the datasheet. The one side of the coil should go to pin 8 and the other side is the output voltage. The device is capable of an output voltage between 0.8 to 5.5V. I have a feeling the output (if the chip is working which I doubt it is because the input voltage was way over maximum allowed) should be either 3.3V or 5V. Most electronics use 3.3V. Check the chip output. If it is bad I am not sure where to get another one. Digikey does not have it. You may have to search the internet to find a supplier.

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#### dcbingaman

Joined Jun 30, 2021
476
I think the buck converters inductor is the large black item that has 100 on the top of it. To check it turn the board over. If it is not a SMD part you should be able to check the resistance between the two terminals. I do not know what the exact value will be but most likely a few ohms to a few hundred ohms. That will identify the inductor. It is highly unlikely the inductor is damaged.

#### dcbingaman

Joined Jun 30, 2021
476
Tried to find a supplier for the buck regulator. Best I could do is Amazon had it at $12 and something odd cents. Do you have a soldering iron and are you comfortable replacing SMD parts? If this part is bad, there is no guarantee that other parts are bad as well. If you find that chip output is not good, you will need to order one. There may be cheaper suppliers, but I am having trouble finding any. This is a gamble you would be taking if that part is bad. We could replace that part and still find other things wrong. Thread Starter #### Kamal1300 Joined Aug 14, 2021 8 Tried to find a supplier for the buck regulator. Best I could do is Amazon had it at$12 and something odd cents. Do you have a soldering iron and are you comfortable replacing SMD parts? If this part is bad, there is no guarantee that other parts are bad as well. If you find that chip output is not good, you will need to order one. There may be cheaper suppliers, but I am having trouble finding any. This is a gamble you would be taking if that part is bad. We could replace that part and still find other things wrong.
Can you please send me the link to the one you found please ? And I greatly appreciate your help , What should I type for finding this on eBay as I do have an account

#### dcbingaman

Joined Jun 30, 2021
476
Right below the inductor is a blue capacitor that has a 6.3V maximum rating. This is most likely where the output of the buck regulator is at. One terminal should be grounded and the other connected to the inductor. You can also check the buck regulator output here. I am guessing if the buck regulator is working this should be 3.3V or 5V.

#### Kamal1300

Joined Aug 14, 2021
8
Tried to find a supplier for the buck regulator. Best I could do is Amazon had it at $12 and something odd cents. Do you have a soldering iron and are you comfortable replacing SMD parts? If this part is bad, there is no guarantee that other parts are bad as well. If you find that chip output is not good, you will need to order one. There may be cheaper suppliers, but I am having trouble finding any. This is a gamble you would be taking if that part is bad. We could replace that part and still find other things wrong. Yes I can replace this as I used to replace EEPROM 8 leg chip from SRS airbag modules for removing crash data and rewriting factory data #### dcbingaman Joined Jun 30, 2021 476 Can you please send me the link to the one you found please ? And I greatly appreciate your help , What should I type for finding this on eBay as I do have an account Just type in the part number APW8720 you want the 8 lead SOP-8 package. But you need to look at the input voltage to it and the output voltage to verify if it is bad or not. Last edited: #### dcbingaman Joined Jun 30, 2021 476 #### dcbingaman Joined Jun 30, 2021 476 Hello I’m Kamal from Beiruit Lebanon coming here for some assistance. I have a TP-Link router that stopped working after I accidentally used a 24V 0.38A power adapter when I should of used the 12V 1.5A adapter instead. The router lights now flicker on and off and then gradually fades away. I am good with micro soldering but don’t have much knowledge in chips transistors capacitors. Can anyone tell me what likely needs replaced or how to diagnose. I do hear some static coming near one of the Capacitors each time the flickering occurs. The average monthly income here is 60$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
Do you have an ESD wrist strap? The part is most likely ESD sensitive.

#### Kamal1300

Joined Aug 14, 2021
8
Do you have an ESD wrist strap? The part is most likely ESD sensitive.
No I don’t have one , I can’t tell you how much I appreciate your help . Your awesome man

#### Kamal1300

Joined Aug 14, 2021
8
Do you have an ESD wrist strap? The part is most likely ESD sensitive.
I can burrow one from my buddy

#### Kamal1300

Joined Aug 14, 2021
8
Do you have an ESD wrist strap? The part is most likely ESD sensitive.
One last question please, my neighbor has a lot of scrap electronics laying around , how can I know what electronic might have this exact chip? Does the last letter APW8720(B) or the bottom numbers matter? Or as long as it says APW8720 ?Thanks again

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#### dcbingaman

Joined Jun 30, 2021
476
No I don’t have one , I can’t tell you how much I appreciate your help . Your awesome man
One last question please, my neighbor has a lot of scrap electronics laying around , how can I know what electronic might have this exact chip? Thanks again
It is hard to tell. Every manufacturer uses different chips for voltage regulators. You may find one, but I doubt it because everyone uses all sorts of different parts but it cannot hurt to look around and try. Almost every electronic piece of equipment requires voltage regulators but there are thousands of different voltage regulators on the market.

#### Kamal1300

Joined Aug 14, 2021
8
It is hard to tell. Every manufacturer uses different chips for voltage regulators. You may find one, but I doubt it because everyone uses all sorts of different parts but it cannot hurt to look around and try. Almost every electronic piece of equipment requires voltage regulators but there are thousands of different voltage regulators on the market.
fair enough god bless you

#### dcbingaman

Joined Jun 30, 2021
476
No I don’t have one , I can’t tell you how much I appreciate your help . Your awesome man
Happy to help! May God give you success at fixing it.