Daewoo KOG-374R0S Microwave Oven User Manual


 
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PRINTED CIRCUIT BOARD <KOG-373R0S, KOG-393R0S>
1. CIRCUIT CHECK PROCEDURE
1. Low Voltage Transformer check
• The low voltage transformer is located on the P.C.B.
• Measuring condition: input voltage : 230V/Frequency : 50Hz
2. Voltage check
• Key check point
• Check method
NO CHECK POINT REMARK
1 IC 1 PIN 2, 21, 30, 34 –5 VDC
2 IC 1 PIN 35
3 IC 1 PIN 31 OR 32
NOTE :
Each measure point must be measured with GND points.
NOTE :
1. Refer to Circuit Diagram (point 4).
2. Secondary side voltage of the low voltage transformer changes in proportion to fluctuation of power source voltage.
3. The allowable tolerance of the secondary voltage is within ± 5% of nominal voltage.
T
0V
–5V
T: 250 ns (4MHz)
0V
T
–5V
Terminal Voltage
4-7
LOAD
AC 25.8 V
NO LOAD
AC 28.4 V
NO MEASURE POINT WAVE FORM REMEDY REMARK
1 MP1 DC -5V±0.25V Replace VL1, EC1 NO LOAD
2 MP2 DC -12V±2.0V Replace EC2, D10, D11, D12 NO LOAD
T:20ms(50Hz)