How to measure the electric cooker with a multimeter for maintenance
1. Maintenance procedure for circuit board burning IGBT or fuse
If the current fuse or IGBT is burnt out, this part cannot be replaced immediately. It is necessary to confirm that the following other parts are in normal state before replacing, otherwise, the IGBT and fuse will burn out again.
1. Visually check whether the current fuse is blown
2. Check whether the IGBT breaks down:
Use a multimeter to measure whether the "E"; "C"; "G" of the IGBT have a breakdown between the three electrodes.
A: "E" pole and "G" pole; "C" pole and "G" pole, positive and negative tests are not conducting (normal).
B: The red pen of the multimeter is connected to the "E" pole, and the black pen is connected to the "C" pole, there is a voltage drop of about 0.4V (the model is GT40T101, all three poles are unconnected).
3. Measure whether the transformer is broken, the normal state is as follows:
Use a multimeter to measure the secondary resistance of the transformer to about 80Ω; the initial pole is 0Ω.
4. Whether the rectifier bridge is normal (test with multimeter diode file):
A: The red pen of the multimeter is connected to "-", and the black pen is connected to "+", there is a voltage drop of about 0.9V, and there is no display when it is reversed.
B: The red pen of the multimeter is connected to "-", and the black pen is connected to the two input terminals respectively, there is a voltage drop of about 0.5V, and there is no display when it is reversed.
C: The black pen of the multimeter is connected to "+", and the red pen is connected to the two input terminals respectively, there is a voltage drop of about 0.5V, and there is no display when it is reversed.
5. Check capacitor C301; C302; C303; whether it is damaged by heat. (if damaged deformed or burnt)
6. Detect whether the chip 8316 breaks down:
Measurement method: use a multimeter to measure the 8316 pins, and there must be no short circuit between 1 and 2; 1 and 4; 7 and 2; 7 and 4.
7. Whether the insulation protection of the thermal switch at the IGBT is damaged.
2. Poor button action
1. Measure whether the CPU port line breaks down:
Use the diode gear of the multimeter to measure the CPU pole and the ground terminal, and there is a voltage drop of about 0.7V. The red pen of the multimeter is connected to "ground"; the black pen is connected to "each pole of the CPU".
Three, the power can not meet the requirements
1. Coil plate short circuit: test the inductance of the coil plate: PSD coefficient is L=157±5??H, PD series is L=140±5??H.
2. Whether the distance between the pot and the coil plate is normal.
3. Whether the pan is the specified pan.
4. Check whether all vital parts are loose and complete.
Inspection of bad condition after assembly:
1. No heating: Check whether the transformer has broken legs.
2. Long beep after plugging in: Check whether the temperature switch terminals are well connected.
3. Unable to power on: Check whether the thermistor terminals are well connected.
4. No small object detection (no alarm): check whether the resistors R301~R307 are normal.
R301~R302 is 68KΩ
R303~R306 is 130KΩ
R307 is 3.0KΩ
5. The fan does not turn; check whether the transistor Q2 is burnt out. (Generally, the heel of the burnt triode has turned yellow; it can also be measured with the diode file of a multimeter)
