{ 35 } feet MCU reset port , after power on reset .

    { 36 } feet remote control input signal when the input signal from the remote control pin should pulse waveform , when there is no remote control input is high .

    { 37 } as the feedback pin fan speed signal for detecting speed.

    { 41 } { 42} pin external quartz crystal oscillator circuit provides a clock signal to the chip.

    { 47 } ~ {50 } feet , respectively, at room temperature , pipe temperature , defrost input , thermal protection signal input.

    { 51 } ~ { 60 } feet to the display circuit, when there is a signal , respectively, as operating instructions , timer instructions , filters clear instructions.

    { 62 } ~ { 64 } feet as IC203 driver module signals , control signals when there is a four-way valve relay , outdoor fan relay , working status of the compressor relay.

    2 . Three necessary conditions microcomputer chip works:

1 ) Power supply voltage (+5 V); 2) reset signal ; 3 ) clock signal ( oscillation signal ) .

Maintenance Analysis: When servicing microcomputer systems, electronic maintenance personnel can be the basis of the weak "black box" approach , coming microcomputer control board as a black box , as long as the figure out of the box and the signal line input devices , output devices and signal lines can be analyzed to determine the possible component failure , and peripheral components to detect the black box according to symptoms. If the peripheral device is normal, and the air conditioner does not work, initially concluded that faulty computer control panel , can be used to check an alternative method. Usually less chance of damage computer chips , while the external components and cable failure rate is high . From the point of view of work equipment , electronic control system is damaged , not working properly can cause the compressor fan motor does not work or does not work .

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