Repair Method: After replacing the same model power transformer, the fault was eliminated. Data source: Beijing Gree Air Conditioning Repair Center http://blog.163.com/gree_ktwx. Analysis and Maintenance: In this machine, the 220V power supply passes through a fuse (3A) to the power transformer, which then outputs 9V and 13V AC voltages after transformation. These are rectified and stabilized by three-terminal regulators 7805 and 7812, respectively outputting +5V and +12V. The +5V supplies power to the microcomputer PD75028 and reset circuit, while the +12V supplies power to the drive IC and relay. First, check that the 220V power supply is normal and the 3A fuse is intact; then measure the chip's +5V voltage at 0V, with no +5V output from the three-terminal regulator 7805. Also, there is no voltage output from the secondary of the power transformer, although there is a 220V AC voltage input on the primary side. Based on this, it can be judged that the transformer is damaged. Gree split-type air conditioner, entire unit does not start. Fault Phenomenon: Neither remote control nor manual emergency switch can turn on the machine, and neither the buzzer nor the indicator light has any response.