The most common faults and solutions for small ultrasonic cleaners
The small ultrasonic cleaning machine is also called single-tank ultrasonic cleaning machine. The ultrasonic working time can be adjusted arbitrarily from 1 to 20 minutes, and it can work for a long time. It is suitable for use in different places. Troubleshooting method: single-slot ultrasonic cleaning machine is relatively simple. Ultrasonic transducer (shock) and circuit board are composed of two parts. The bottom cover is removed, the two leads of the positive and negative poles of the transducer are unplugged from the circuit board, and then the two ends are detected by a digital multimeter 20nf capacitive gear. It shows that 4.12nf is basically normal, remove the circuit board (the circuit board has more than 20 components such as transformer, inductor, fixed capacitor, diode, resistor and fuse). Visually, it is found that the resistor R1 has a crack and R1 is a 2.2Ω. The /2W current-limiting resistor has been disconnected after soldering (estimated to be caused by a short circuit of the power transistor D304X). As the two power transistors are soldered and tested, they are all broken down. Further testing is performed and no other components on the board are abnormal. Replace the upper limit current resistor; replace the two transistors with the switch transistor J13009 and increase the heat sink appropriately. Then, connect the two leads of the positive and negative electrodes of the ultrasonic transducer to the main board, add water to the container, turn on the power, and the washing machine works to return to normal.
Later, we have repaired two different ultrasonic cleaning machines of different grades (although the circuit is slightly different, but the principle is similar), after detecting the faulty parts and the first one, they are all 2W2.2Ω current limiting resistors. Break and power transistor breakdown damage.
It is worth mentioning that after the ultrasonic cleaning machine is repaired, the reliable grounding of the transducer must not be ignored. Because the voltage output to the transducer is high and the transducer is in close proximity to the wash basin, it is quite dangerous in the event of a leak.