If the oven heating tube is broken, first of all we have to check whether the temperature control system is faulty. If the temperature control system fails, then the heating tube will burn out without temperature control. If the temperature control system is not broken, then it is necessary to detect whether the heating tube is burnt out. Use the resistance gear of the multimeter to measure the resistance of the heating tube terminal to see if the heating tube is connected. If it is on, the heating wire in the heating tube is good.
Use the resistance gear of the multimeter to measure the resistance of the heating tube terminal and its metal tube to see if its resistance is close to infinity. If the resistance is close to infinity, the heating tube is good. The heating tube is a resistive load. You can first test whether the circuit is open. You can use the 20M file to test. If the open circuit is definitely broken, then use this file to test whether the shell is short-circuited. If it is short-circuited, it is also broken.
Then use the appropriate gear to measure the actual resistance value of the heating tube, according to: resistance value = voltage * voltage/power, conforming to this value indicates that the heating tube is good.
