Air Conditioner Service Manual 
 
38 
 
terminal L and N (before display of E0 fault). If the voltage is “0”, please replace indoor main PCB. 
     
2) If the 1 & N which connect to indoor unit voltage is normal, measure the voltage between the outdoor 
terminal 1A, 1B, 1C, 1D and N. If the voltage change occurs between 0~24V (change pulse voltage), 
please replace  indoor main PCB. 
     
3) If the 1A, 1B, 1C, 1D & N which connect to indoor unit voltage is normal, measure the voltage between 
the outdoor  terminal 1 and N. If the voltage change occurs between 0~12V( change pulse voltage), but 
there is no  24V, please replace the outdoor PCB. 
     
 
4) If the 1, 1A, 1B, 1C, 1D & N voltage is normal, measure the voltage between the outdoor terminal 1 
and N. If the  voltage has no change, firstly replace the indoor main PCB. If the fault remains 
unsolved, replace the  outdoor PCB. 
     
 
5) Communication fault if resistance or optical coupler broken, replace outdoor PCB. 
Is there any burnt on PCB?    If no, test the rectifier, FRD, IGBT etc. any component broken, replace PCB.