If it is found that the distance of the remote control remote control too close or remote control doesn't work, consideration should be given to the infrared receiving head circuit is at fault. The judgment of an infrared receiving head is normal or not, the following several methods commonly used:
1 using the oscilloscope observation of an infrared receiving head signal output, the antenna input with a metal point contact of an infrared receiving head, clutter reaction oscilloscope should be more strong, otherwise the description of an infrared receiving head part of a fault.
2 use the remote control signal, using a multimeter voltage DC voltage range measuring signal output end, when you press the remote control key, should change its output voltage, without any reaction, that of an infrared receiver circuit failure.
3 use the remote control signal, using the oscilloscope to observe the output of an infrared receiving head end ("OUT"), decoding circuit input due to pulse signal output. Due to the transmitted data signal waveform is different, the burst width different combinations, such as waveform is not normal or undetectable waveform, description of an infrared receiving head part of a fault.
4 will be receiving antenna spectrum analyzer near infrared receiving head, to the remote control system (or an infrared receiving head) power, 400MHz band should be observed in wavy (adjustable capacitive) or inverted "V" shape (adjustable) spectrum waveform, such as spectrum analyzer screen without any reaction, description of an infrared receiving head circuit failure.
