V4+R VRF 50/60Hz       
66    201608 
Midea V4+R Series Service Manual 
 Procedure 4.9.4
 
Power supply for main PCB and 
transformer is abnormal
1
 
Provide normal power supply 
The transformer has malfunctioned
2
 
There is a source of electromagnetic 
radiation near the unit, such as 
high-frequency transmitter or other high 
strength radiation device 
Remove the source of interference 
 
Notes:   
1.  Measure the voltages of ports CN31, CN33 and CN35 on the main PCB (labeled 8, 9 and 24, respectively, in Figure 5-2.1 in Part 5, 2.1 “Ports”). The normal 
voltage between CN31 and CN33 terminals is 220V, between GND and the 5V pins of CN35 is 5V, between GND and 12V pins of CN35 is 12V. If one or more 
of the voltages are not normal, the power supply for main PCB and transformer is abnormal. 
2.  Measure the voltages of ports CN32 and CN34 on the main PCB (labeled 18 and 19, respectively, in Figure 5-2.1 in Part 5, 2.1 “Ports”). The normal voltage 
across the upper two pins of CN32 is 13.5V (AC), across the lower two pins is 9V (AC). The normal voltage across the upper two pins of CN34 is 14.5V (AC), 
across the lower two pins is 14.5V (AC). If one or more of the voltages are not normal, the transformer has malfunctioned. Refer to Figure 5-4.2. 
 
Figure 5-4.2: Transformer power output terminals 
 
   
CN34: No.2 transformer 
power output 
CN32: No.1 transformer 
power output