1. Invalid operation

This kind of fault means that after power on, press the manual or remote control button, the fan does not turn, and the indicator light is not on. In this case, check whether there is – 5V voltage at both ends of C4. If not, check whether the power fuse, step-down capacitor C1 and rectifier filter system are normal. The common causes are fuse fuse or breakdown of – 5V regulator D3 (1N4733A). If the voltage is normal, check again whether some of k1-k5 on the panel can not be reset or whether the printing board where IC1 and the key are located is affected by moisture, which causes the IC1 program cannot be reset and cannot be started.

If all the above are normal, the replacement method should be used to check whether the crystal oscillator has deteriorated and whether the solder joint of IC1 and crystal oscillator has false soldering with a magnifying glass. If no abnormality is found, IC1 may be damaged.

Remote control electric fan maintenance circuit diagram

2. The motor does not rotate

This kind of fault means that after pressing the “start / speed regulation” key, the wind type display green LED can be on, but the motor does not rotate. The fan head protective cover can be opened. When the fan is powered on, the fan blade can be moved by hand. If the fan can rotate, it may be that the starting capacitor or the starting winding of the motor are damaged, which can be inspected separately. If it is obviously hard to move, it may be that the bearing is seriously short of oil or the rotating shaft is displaced, resulting in the rotor “sweeping” (rubbing with the stator coil). At this time, you can add oil to the bearing (or replace it with a new bearing) or knock the back cover with a wooden hammer to see if it can be solved. If not, the motor can only be replaced. If it is hard to move the fan blade after power on, and the “buzz” sound can be heard, but it is easy to move after power failure, then the working winding is seriously short circuited. At this time, if there is no condition for self winding, only a new motor can be used. If it is easy to move and can’t hear “buzzing” sound, ohmmeter can be used to measure the resistance of working winding (between gray and black wire ends). If it is infinite, it indicates that the temperature fuse of motor is damaged (at the place where the inlet port is close to the shell, similar to small ceramic capacitor). In case of emergency, it can be replaced by 0.1 Ω ~ 1 Ω / 0.5W fuse resistance. If the resistance value is normal (20 Ω), then measure the resistance between the gray wire and the red, white and blue wire ends in turn, which should be increased evenly in turn. If the resistance value changes suddenly or infinitely, it means that the internal winding has local short circuit or open circuit phenomenon, so the motor can only be rewound or replaced. If the measured resistance between the gray line and the red, white and blue wire ends increases evenly, it may be that the bidirectional thyristor tr1-tr3 is open circuit or IC1 is partially damaged, and the corresponding ports (2), (3) and (4) pins are not sent out low level, resulting in the motor not powered on and unable to run. Check the voltage between the gray line and the red, white and blue wire ends. If there is no voltage, check whether the IC1 (2), (3), (4) pins output low level to confirm.

3. It can operate, but can’t adjust the speed

If the corresponding wind speed indicator lights up after pressing the “start / speed regulation” key, it indicates that there is breakdown damage in tr1-tr3. If the speed control indicator is not on, it may be that IC1 is partially damaged or the “start / speed regulation” button fails. However, damage to the same button on the remote control and panel is rare.

4. Unsmooth head shaking or failure

If the “horizontal” (or “vertical”) shaking button is operated after the machine is turned on, the corresponding shaking indicator will also be displayed, but it will not shake its head. The lead wire of horizontal (or vertical) moving head synchronous motor can be welded and directly connected to AC220 V power supply to observe whether the motor can rotate. If there is no response, the corresponding synchronous motor is damaged and should be repaired or replaced. If it can rotate, the bidirectional thyristor Tr5 (or TR4) is damaged and can be replaced by the common model bcr3am. If the machine does not shake its head smoothly (uneven rotation or shaking), it is generally caused by excessive clearance or lack of lubricating grease between the crank and the synchronous motor in the head of the machine. If the former, adjust or replace the horizontal (or vertical) head crank to make it contact closely. If the latter, add grease. If it is invalid, it may be that the motor “sweeps the bore” due to serious wear of the bearing, so it can only be replaced with a new bearing.

5. Remote control operation is not allowed

This may be due to damage to the remote transmitter or receiver head. The remote control transmission circuit of the fan is shown in the figure below. The pins (6), (7), (9) ~ (12) of the transmitter chip IC2 (rts715-2) are empty pins, and the 120K Ω resistance connected to pins 13 and 14 constitute an oscillation circuit, which generates carrier signal, encodes the data input from pins (1) ~ (5) and outputs them in series by pin (15), and then drives infrared emission after being amplified by transistor s8050 The tube sends out a remote control signal.

When remote control is not possible, first of all, check whether there is an infrared signal from the infrared transmitting tube when pressing the relevant control button (the method is introduced in many materials, such as monitoring with radio). If not, check whether the 3V power supply of the remote control is normal (whether the contact is good). If it is normal, check whether the remote control keys connected to IC2 (1) ~ (5) pins are short circuited, leakage or open circuit. When the conductive rubber powder falls off and causes the control switch short circuit, the remote control chip can not work normally. If the conductive layer above the control button falls off completely, the control command can not be input, which also leads to the failure of remote control. If the infrared remote control signal is sent out when the remote control button is pressed, it can be concluded that the remote control receiver head is damaged. It has been proved that the receiver head of the fan can be replaced by the commercially available remote control receiver head of color TV set. It is only noted that the original grounding terminal of the remote control head is connected with a 5V, the original + 5V (power) terminal is grounded, and the signal output line is connected to the IC1 (17) pin (the same as the original).

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