Easun IGrid SS 3KW Plus, Service Manual, Page: 27 / 29

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Q10,Q2,Q16,Q8
(B,E) Diode Voltage Droop
 0.6V
Short or open
(B,C) Diode Voltage Droop
 0.6V
Short or open
Note: 1. If MOS or RESISTOR is damaged, it means that the Optocoupler
(U1&U2&U3&U4) may also be damaged extremely. So replace it at the same time.
2.Make sure the voltage of capacitor C22,C24 is less than 0.1Vdc when test QA1,
QA2, QB1, QB2, QC1, QC2, QD1, QD2.
7.2.2.3 Major parameters of main SPS section
The most likely problems occur on the SPS section including broken MOSFET, broken
Diode, damaged sense resistor, damaged relative driver resistor with broken MOSFET.
Checked components Instrument function
Reference
Value
Failed Condition
Q2
(S, D) Diode Voltage Droop
 0.5V
Short or open
(G, S) Resistance

47kΩ Short or open
R11 Resistance

0.5Ω
Infinite or value
change
R7 Resistance
 100Ω
Infinite or value
change
D1, D7, D6, D3, D2, D20 Diode Voltage Droop

0.45V Short or open
U3
Power Pin(Pin7-Pin5) Resistance

230KΩ Vcc short to GND
o/p Pin(Pin6-Pin5) Resistance  47kΩ Short or open
U4
Pin1-Pin2 Diode Voltage Droop

1.0V Short or open
Pin3-Pin4 Resistance  440kΩ Short or open
7.2.2.4 Major parameters of DISCHARGE section
The most likely problems occur on the DISCHARGE section including broken MOSFET,
broken Diode, damaged relative driver resistor with broken MOSFET, broken fuse.
Checked components Instrument function
Reference
Value
Failed
Condition
Q1,Q2,Q3,Q4,Q5,
Q6,Q7,Q8,Q9,Q10
(S, D) Diode Voltage Droop
 0.5V
Short or open
(G, S) Resistance

4.7kΩ
Short or open
R1,R2,R3,R4,R6,R7,R8,R14,R15,R16
R17,R19,R20,R21
Resistance
 10Ω
Infinite or value
change
D1,D3(need be removed from PCB) Diode Voltage Droop

0.6V Short or open
U1,U2
Power Pin(Pin4,5-Pin2,7) Resistance >10KΩ
Vcc short to
GND
o/p Pin(Pin3-Pin2,7) Resistance

10kΩ Short or open
F1,F2,F3,F4 Resistance  0Ω open