This machine failure phenomenon of open cooling, indoor machine panel light is normal, fan operation is normal, after waiting for three minutes, indoor fan stop running, light is shining. Restart after shutdown, repeat the above phenomenon. E7Xservice manual download site
 E7Xservice manual download site
After the restart the air conditioning, immediately see the machine, three minutes later, the machine compressor, fan, but after a second, compressor stop running immediately. From the compressor start instantly sound judgment, compressor is not lack of phase, the compressor motor is normal. Open the enclosure, three-phase voltage is normal. After power, compressor three-phase motor coil resistance measurement are normal, check the cooling fluid is not short of. Preliminary judgment for fault protection. E7Xservice manual download site
 E7Xservice manual download site
 E7Xservice manual download site
Observe the electronic circuit inside the complex, outdoor large PCB with SMT components and integrated block, can not see where corrosion, but there were big circuit board, and a small circuit board, models for PBZ - TU70, full use of discrete component, resistance, capacitance and diode are not SMT components, so it was serious corrosion. From the circuit board connection, is testing the status of the compressor. To determine the air conditioning fault has relationship with the small circuit board. Removed this board, measure has rusted diode foot is broken, a touch of the diode have been broken, can't see model, change into a common rectifier diode, measured with a multimeter electric block other elements not found the problem, on a small plate, air conditioning runs normally. E7Xservice manual download site
 E7Xservice manual download site
Now painted schematic diagram small circuit boards, and measure the components parameters, for reference, as shown in figure. E7Xservice manual download site
 E7Xservice manual download site
From schematic diagram analysis: compressor phase wire bunch of coil CT1, some current size perception from CT1 compressor. When the compressor current normal get ac CT1 after diode rectifier, the C2 filtering. By R2, R3 after partial pressure, normal size in CN1 plug dc current to the circuit board, control of compressor startup. Such as diode is broken, there is no dc voltage of the CN1, big circuit board for the compressor running current is too small, or lack of phase, thus unable to start the compressor.

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