Midea 22033010000701, Service Manual

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ServiceManual_2018-V1.0
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10. Circuit description
10.1 Power Supply
AC input power is reduced into 12V by means of TOP chip switch on/off and T1 transformer, then output stable
DC12V by LC filtering, ,DC12V is for provide power to relay(control strong electricity),lamp, electric valve and so
on, the relay controls on-off of the compressor, defrost heater, and some strong electric components. DC12V is
reduced into stable DC5V for provide power to MCU, it monitors the temperatures of refrigeatorIf no power
detected in test, firstly check whether there is input voltage between the L& N line of main PCB, if no input
voltage(115V/230V), please check whether there is power supply in the socket; if there is input voltage, put the
black probe of multi meter on the bottom of “GND” pin, and put the red probe on the bottom of “+5v” or “+12v”
pins, if there is “12v” or “5v” detected, check whether there is loose connection with these wiring connectors; if
there is no “12v” or “5v” detected, it means the main PCB is damaged, replace it by a new one.