Gree      GMV6 DC Inverter VRF Units Service Manual 
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(1)  Before the inspection: Find a correct digital multimeter and switch it to the diode gear. Power off the 
unit and wait two minutes. Disconnect the U, V and W cables of the fans from the drive board. Do 
not operate without waiting two minutes after the unit is powered off. 
(2)  Testing method: Point the black probe of the multimeter to the P bonding pad shown in the following 
figure and the red probe to U, V and W wiring terminals respectively and check the readings of the 
multimeter; point the red probe of the multimeter to the N bonding pad shown in the following figure 
and the black probe to U, V and W wiring terminal respectively and check the readings of the 
multimeter. 
(3)  Result analysis: If all the readings of the multimeter are between 0.3 V and 0.7 V in the above six 
conditions, the module is normal; if any of the readings is 0, the module is damaged. 
 
 
4.9 Main Board 
The main board is used to control the load of the ODU.