Solution: Replace with the same model crystal oscillator to eliminate the fault.
Haier KFR-32GW type split air conditioner, remote control malfunction.
Fault Phenomenon: Pressing various function keys on the remote control shows corresponding displays on the screen, but when aiming the remote control at the air conditioner's receiving end and pressing various buttons, the unit has no response at all.
Analysis and Repair: Preliminarily judged that the signal transmission part is damaged. Connect a multimeter in series in the power circuit of the remote control, check the static current which is about 2mA, but the dynamic current is only 3mA, indicating that the CPU is normal, but there is no normal infrared remote control signal emission. Draw out a wire from the positive terminal of the battery, connect a 1kΩ resistor in series, and touch the base of the transmitting transistor with the other end. The transmission current rises to 35mA, indicating that the transmission circuit is good, and the fault lies in the absence of encoded carrier frequency signal output. The remote control itself has display, indicating that the CPU clock is fine, but the crystal oscillator (400-600kHz) used for modulated encoding transmission is damaged and cannot form an infrared signal transmission pulse. Use a soldering iron to unsolder the crystal oscillator, place it near your ear and shake it, you can hear a slight "rustling" sound, judging that the crystal oscillator is damaged.
Source of article: Beijing Haier Air Conditioner Repair Phone; Beijing Haier Air Conditioner Repair Phone http://blog.tianya.cn/blogger/blog_main.asp?BlogID=3467495.