The car radio is connected backwards, and the positive and negative poles are white smoke.

Accidentally connected the positive and negative electrodes, white smoke came out. It is normal to start playing now.

According to this situation, there will be three kinds of white smoke:

1. The electrolytic capacitor on the amplifier board is damaged, which is the black one in your picture. You can check whether there is electrolyte leakage under the capacitor.

2. Check whether there is a zener diode, weld a pin, and check whether the zener diode is damaged. The voltage stabilizing tube is connected in reverse parallel to the power supply circuit.

3. The reverse connection of the power supply may lead to an abnormal increase in the current of the whole circuit. After the current increases, some resistors may emit white smoke under the condition of high current. This situation is not a big problem. After the power supply is restored, there will be no obvious influence on the resistance, but the resistance value may change a little, as long as it does not affect the use.

4. Another possibility is that the audio amplifier module is injured, that is, the two components circled in red on your drawing. However, this kind of audio module generally has overcurrent protection inside. As long as it works, leave it alone for the time being. The power supply voltage of the car radio is 12V (24V for gasoline and diesel vehicles). The back of the audio power amplifier module is generally connected to the chassis or aluminum radiator for heat dissipation. In order to ensure good heat dissipation, thermal conductive silicone grease will be coated between the power amplifier module and the radiator. It is also possible that when the temperature of the power amplifier module rises after you connect the reverse power supply, the thermal conductive silicone grease will be burned off. You can check it, then re-coat it with heat-conducting silicone grease, and then fix it firmly with a shell or aluminum radiator to see if the temperature has dropped. If the fault still exists, it is recommended to replace the audio power amplifier module according to the original model. According to the picture of the circuit board you provided, your audio amplifier module may be TDA2002, TDA2003, TDA2030.

TDA2002 working voltage = 5 ~ 20V output current.

The working voltage of TDA2003 is 12V-24V, the normal working voltage is 8- 18V, and the output power is 18W. USB5V does not work.

The typical working power supply voltage of TDA2030 is 14V, and the normal working voltage is 6- 18V.

When replacing components, it is recommended to use a tin sucker and a constant temperature soldering iron for replacement.

If you still don't know what the problem is, you can check whether the voltage of the power supply circuit is normal. Then check the input signal and output signal voltage of the audio power amplifier module, and then make a judgment.

● The above content is "I don't know", written according to my personal experience. The above contents shall not be copied or modified without authorization. If you want to quote, you need to indicate the source.