[BK7231N] Aubess Mini Switch 16A - Not work with mains only by UART

Hello everyone,

First, excuse me if this post doesn't belong here. Please move it to the appropriate section.

I have flashed [BK7231N] Aubess Mini Switch 16A, specifically this model (https://obrazki.elektroda.pl/1767744100_1682576225.jpg).

Everything works correctly with the UART converter soldered, however, if I connect it to 230v, it doesn't work.

When the UART converter is connected, it works, even the Relay slightly. This led me to check the 3.3v output and saw that it is actually 4.3v. I understand that this causes the relay to activate, but could I have damaged the power circuit?

So far, I have used this converter with more than 30 devices without problems.

Hello, can you be a bit more specific? What does not work? Does it connect to your WiFi when powered from mains?

Are you able to check for the 3.3V presence while it's being powered from mains? Just be sure that you can do that in a safe manner. Mains voltage is deadly dangerous.

Was it working with mains before firmware change?

I mean that when I connect it to 230v AC, no LED lights up or it connects (verified in the router logs) to my Wi-Fi network. (Preconfigured from UART)

I can do any measurement but I am not able to identify the voltage regulator at 3.3.

Before replacing the firmware it worked apparently fine. I mean, it turned on the led, activated the relay and went into AP mode. I didn't get to link it with any app.

Thanks for your answer so much!

I am attaching a photo of my board in case you can tell me where to take measurements.

Maybe you should try to probe those places:

Hello,

I have measured and I have no value in either 3.3v or 5v. Maybe a capacitor or diode is damaged?

Apparently there are no signs of overheating in the components (the board is new).

Regards!

Is there mains (230V, I would assume? Or are you in 120V area?) at the solder joints of high voltage terminal?

Please do all measurements with caution. If you are not confident about your skills and safety, don't do it.

Hello,

My network is 230V (Spain) and in the measurements, the equipment was connected and with 225V approx between L in and N out.

I have tried with another device that I have that does not work well (the UART does not detect it and it does not start with the original fw either), but the regulator values give exactly 3.3V and 5V.

I think it may be a fault in the high voltage circuit. Where would you go?

Don't worry about safety, the line is protected with a circuit breaker and differential (30 mA) exclusive to the workshop .

Regards, and thank you very much.

Edit:

After measuring capacitors and diodes, I noticed that one of the coils (located near R1) was open. One of the wires had become unsoldered from the pin (perhaps from a blow).

I have replaced it, and after that, everything works fine.

Thank you very much for the help.

You can close the thread. All the best.

I am glad to hear it's solved. It is very important to investigate whole circuit, step by step, in case of faults like this. That way you can quickly determine what's wrong.

Please open a new topic if you have any further questions, I'll be happy to assist you further. I am closing this topic for now.