There are two main types of commercial stoves: one is a gas stove, and the other is a commercial induction cooker.
Commercial induction cookers, like other homes, have a certain lifespan. After a certain period of use, some malfunctions may occur, ranging from repairs to scrapping. This is unavoidable for any equipment. When a commercial induction cooker breaks down and needs to be repaired, you need to check it carefully, because some problems with the induction cooker are obvious, but some problems are deeply hidden and can be missed without paying attention.
How to correctly analyze and repair hotel commercial induction cooker failures? Kyoto gives you some diagnostic suggestions.
1. When a customer hands over a commercial induction cooker to you, do not rush to test the machine. You must first inquire about the failure phenomenon of the induction cooker and the specific process and reasons for the damage.
2. If there is oil on the circuit board of the commercial induction cooker, it is recommended that you clean it first. When cleaning, separate the transformer and current transformer, and dry them immediately after cleaning. Induction cooker heating is not normal. Part of the reason is that the IGBT drive tube pins are too dirty and leakage. Moisture on the electric board can also cause various inexplicable failures. To repair the induction cooker, it is best to use an oven and temporarily modify it with a scrapped microwave oven. ,Economical and practical.
3. When repairing a power circuit failure, if the input voltage is 18V, please measure whether there is 19V voltage on the positive pole of D31. If there is 19V voltage, it can be judged that D31 is open circuit. If there is no 19V voltage, please measure whether the positive electrode of the EC22 capacitor has a 19V voltage. If there is a 19V voltage, it means there is a problem with the voltage transformer l101. Replace it to resolve the fault.
4. When measuring electronic components, it is recommended to disconnect them from the circuit to avoid errors. Weak soldering of the pins of the filter, resonant capacitor and constantan wire, and interference in the sampling circuit wiring are common soft faults of induction cookers. What is required is careful observation. I repaired a wonderful induction cooker repair board a few days ago, and there was an alarm sound, but There is no PWM pulse signal output. After replacing the 339’s 2-pin and 5-pin parallel film capacitors (2A103J), the fault is eliminated. Some faults should not be restricted by experience, but also need to be boldly innovative.
5. To repair the fault of the bit circuit, when the voltage of pin 8 of the main chip is measured to be 0V, you can measure whether the base of Q3 has a voltage of +2.2V. If not, check R61, Z1, and R16. If the voltage is normal, you can use a multimeter to carefully check whether the following components: Q3, R4, and C7 are normal. If the components are normal, you can replace the main chip.
6. For induction cookers that burn IGBT, in addition to checking the cause, you should also promptly replace the limiting voltage stabilizing diode. If there is no limiting stabilizing protection circuit designed, you should directly replace the driver pair. No matter what the fault is with the induction cooker that has been idle for too long, it is recommended to check the resonance. , two large capacitors for filtering. The capacity is prone to becoming smaller, failing or defective.
7. When repairing the control board, it is recommended to replace the switch key, because the adhesion of the buttons, leakage of electricity, and leakage of the cable base can cause the inability to turn on or off the machine, confusion of the control panel function, and malfunctions caused by water intrusion into the cover; It is best to waterproof the cover. To prevent the failure from happening again. When repairing the switching power supply, be sure to disconnect the load, because the 5V or 18V input pin of the load component is short-circuited to the ground and leaks, which also causes the switching power supply to have no 5V or low-voltage power supply, and the low voltage is abnormal.
8. Don’t assume that everything will be fine after the circuit board is repaired. It is recommended to check the accessories. Their abnormalities are also one of the main reasons for motherboard failure: a defective wire tray not only damages the terminals, but also causes the IGBT to burn out. A defective fan can cause 18V to be too low. The IGBT burned out, and I also found several cases of induction cookers burning out the switching power supply due to fan short circuit.