Pioneer KYT-3OD remote control fan circuit and maintenance case

The fan is made of plastic, with adjustable frame height, 30cm in size and 45W in power. It has functions such as remote control/manual, 3 wind speeds, 9 wind types, 7.5-hour timing, 3600 blades of air supply and automatic overheat protection. The schematic diagram of the remote control circuit is shown in Figure 1, and the schematic diagram of the receiving/control circuit is shown in Figure 2. The component numbers are noted by the author.

1. Circuit Working Principle

1. Remote control circuit

The remote control circuit is composed of the coding integrated circuit IC 1 (RTS571-2) and its peripheral components, among which IC1's ① to ⑤ pins are the shutdown, on/off speed, wind type, timing, and blade rotation key input terminals respectively; ⑧ pin is connected to the negative terminal of the power supply; ⑩ pin is connected to the positive terminal of the power supply; ⑥, ⑦ and ⑨ to ⑩ pins are left floating and unused; ⑩ and ⑩ pins are connected to external resistor R1, which forms an oscillation circuit with the internal circuit of ICi to generate a 38kHz carrier signal. After being modulated by the function key coding of pins ① to ⑤, the coded carrier signal is output from pin ⑩, amplified by the transistor VT, and drives the infrared transmitting tube LEDI to transmit infrared remote control signals to the outside world to control the working status of the fan.

2. Receiving/control circuit

In Figure 2, IC1's ① and ⑩ pins are connected to an external crystal oscillator B (32.768MHz), which together with the internal circuit form a clock oscillation circuit; the ⑩ pin is connected to an external infrared receiver LEDO, which inputs the remote control signal received from the remote control into the internal decoding circuit, and outputs drive signals from pins ② to ⑥ to control the operating status of M and MS; the ⑧ and ⑨ pins are the common terminals of the function indicator lights LED1-LED10, which together with pins ⑩ to ⑩ form a matrix display circuit; the ⑩ pin is connected to an external buzzer HA, and when each function key of the remote control or manual panel is operated once, the buzzer emits a "beep" sound (when the power off key is operated, the buzzer does not sound), indicating that the operation input is valid, and the corresponding function indicator lights up; the ⑦ and ⑩ pins are connected to the negative power supply; the ⑩ pin is connected to the positive power supply; the ⑤ and ⑩ pins are left floating and unused.

Connect to 220V mains, one route is VD1 outputting a 4.5V DC voltage to power pins ⑦ and ⑩ of IC2, and at the same time, the DC voltage is added to the common end of each button through R4; the other route is VD2 outputting a 4.5V to power the infrared receiving head.

The buttons on the remote control or manual control panel will give you the corresponding functions:

This button is used to start the fan and select the wind speed. When the on/wind speed button is pressed for the first time, the IC2 pin ② outputs a negative level, VS1 is turned on, and M runs at a low speed; when the button is pressed for the third time, IC2 pins ② and ③ have no output; VS1 and VS2 are cut off, the ④ pin outputs a negative level, VS3 is turned on, and M runs at a high speed. Press the button repeatedly, and the wind speed will cycle through the low speed, medium speed, high speed, and low speed modes, and the wind speed indicator LED 1 -LED2 -LED3 -LED 1 will light up accordingly.

(2) Wind type key This key is used to select the wind type. By combining the wind speed key and the wind type key, 9 wind types can be obtained. In the initial state of power on, the wind speed key is in low gear. If the wind type key is pressed repeatedly, the wind type will cycle through the low-speed natural wind, sleep wind, normal wind, and natural wind modes. The wind type indicator LED5-LED6-LED4-LED5 will light up accordingly. IC2 pin ② will intermittently output negative level, VS1 will be intermittently turned on and off, and M will intermittently blow at low speed. When the wind speed key is in medium or high gear, IC2 pin ②, ③, and ④ will output negative level successively, VS1, VS2, and VS3 will be turned on and off successively, and M will intermittently blow at medium or high speed. If the wind type key is pressed repeatedly, the wind type remains the same.

(3) Timing key This key is used to preset the timing. After the machine is turned on, each time the timing key is pressed, the timing indicator LED7 to LED10 will light up in increments of 0.5 hours. When LED7-LED10 are all on, the time indicated is 7.5 hours, and as the remaining time decreases and the indicator lights go out one by one, the fan automatically shuts down.

(4) The blade rotation key is used to control the working state of the impeller. After powering on, press the blade rotation key, IC2) pin outputs a negative level, the blade rotation indicator LED11 lights up, VS4 is turned on, and the MS starts to drive the impeller to rotate 3600 to blow air. Press the blade rotation key again, IC26 pin has no output, LED11 goes out, VS4 is turned off, and the MS stops.

(5) Power off button Press the power off button to reset IC2 immediately, VS1, VS2, VS3, VS4 are turned off, the fan stops working, and the circuit enters the standby state. At this time, the DC power supply circuit is still working. If the fan is not used for a long time, it is generally advisable to unplug the power plug.

FU is an overheat protector, which is connected in series in the motor M circuit and fixed to the motor housing with screws. When the motor temperature rises above 9590, FU will automatically fuse and cut off the motor power supply to protect the motor. The attached table is the measured in-circuit resistance and voltage values ​​of IC2 (RTS511B-000) for maintenance reference.

2. Common fault troubleshooting examples

1: When the wind speed key is set to high, the fan does not rotate, while other speeds are normal.

Analysis and repair: The fault phenomenon shows that the fan is basically normal, and it is limited to the damage of the related components of the high-speed control circuit. Power on, operate the wind speed key to high gear, and measure the negative level of the MIA pin output. It shows that IC2 is normal. Power off, test R10 and VS4, and find that the VS4 shell is cracked. The forward and reverse resistances of the tube T1 and T2 are infinite, which confirms that VS4 breaks down and opens the circuit. After replacing it with a 1 A/400V (MSC97A6) bidirectional thyristor, power on the machine for testing, the fan runs normally, and the fault is eliminated. Example 2: Operate the blade rotation key, the blade rotation indicator light is on, and the impeller does not rotate.

Analysis and repair: According to the fault phenomenon analysis, it is mostly caused by the burning of the blade motor MS. Power on, operate the blade key, and measure the 220V voltage at both ends of MS, indicating that the blade control circuit is normal. Power off, and then measure the resistance at both ends of bIS, which is infinite. The normal resistance is about 7icn. It is confirmed that the MS coil is broken, causing the blade motor to not rotate and causing the above fault. Replace MS (model 49TYJ500/5-6, voltage 220V, power 3-4W, speed 5--6r/min non-directional permanent magnet synchronous motor), and the fault is eliminated.

Example 3: When the wind speed key is set to low, medium, and high, the motor makes a buzzing sound and does not rotate. When the housing is tapped, it can rotate sometimes, but the noise is loud. Analysis and repair: The fault phenomenon indicates that the motor shaft is seriously lacking in oil. Remove the motor cover, pull out the rotor, first use a little gasoline to clean the grease, polish the shaft with 06 metallographic sandpaper, and then inject a few drops of moderately thick four-base silicone oil into the inner hole of the bearing. If this oil is not available, industrial No. 10 engine oil can be used instead.