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Henan YANG Wei Liu Yisheng Transmitter Maintenance of audio with hum Launch pad work in the mountains a thousand guns solid TV Transmitter , There is significant exchange of audio sound, the sound started small and light, and slowly more and more serious, the image has a slight exchange of interference. The transmitter is all solid-state design, Power supply With three independent power supply, 50V voltage of the two groups, 28V voltage of a group, all switching power supply, which is characterized by wide voltage range, high efficiency, power, protection function and so on. According to failure analysis of phenomena, should not the net caused by the power filter. First of all, the power of the machine three groups conducted a comprehensive examination, did not find the problem. Modulated part of the aircraft after the inspection found no abnormalities. Measurement filter Capacitance Discharge normal, replace the capacitor with the same fault model remains. Finally, Oscilloscopes Observations have also found no exchange of power supply components. Then check one kilowatt transmitter forward the signal source??? Microwave receivers, microwave receivers by check out the signal also has drone, with a new microwave receiver replacement, fault still exists. Is it a problem with the host microwave transmitter or signal source is not normal? With a question back to the center of more than a dozen kilometers away transmitters, microwave transmitters was examined and found no problems, but sent a signal source cable network has been normal, that signal is good. So he had to launch pad back to mountains, Tam still can not identify the problem, check the impasse. Inadvertently turned off the monitor signal microwave receiver Monitors (Normal TV custody dual), suddenly found all the normal transmitter signal out, the problem was finally found, the original source of interference from the monitor. The inspection found that the monitor power supply filter capacitor (300V filters) leakage, with no capacity, the same capacitor with a replacement, received a microwave receiver, the transmitter signals pure, no interference, troubleshooting . Summary: Due to monitor long-term work, power supply filter capacitor leakage, loss of capacity, resulting in power supply filter is not clean, 50 Hz AC signal by microwave transmitter within the receiver string to cause interference. This is a special failure, should attract the attention of colleagues, proposed, or using a dedicated monitor at all. Modulator Output image and audio troubleshooting of interference Maiwe modulator is produced by a factory in Shenzhen, the market has a large amount, our station is manageable, in 2001 established a set of additional descrambling system (designed to manage the county seat Cable television Users), the use of modulators are Maiwe license MW-P63M Adjacent modulator, the modulator with IF input and output functions, linear power supply. Use one year after the modulator, the output of 50 Hz serious interference, the image from top to bottom on a rolling bar, audio distortion, and drone sounds great. Open Modulation Used Multimeter 5V regulator output voltage measured normal, 12V is normal, only about 24V voltage is only 18V, 24V careful examination revealed a bubbling phenomenon filter capacitor on top, remove the capacitor capacity is no longer measured with a multimeter (should be 2200 f/25V) , with a new 3300 f/35V 24V capacitor voltage after replacing normal. After the modulator installed back into the system work well interference rule. Seizure modulator in the production process, power supply linear power supply, three groups were using three-terminal regulator output voltage regulator, voltage regulator 24V smaller filter capacitance, low voltage value, I buy Taiwan of these modulators have both been the failure. For using large capacity and high-voltage capacitor, no recurrence of such failure phenomenon. The Editor if: large capacity Electrolytic Capacitor After long hours of work, the electrolyte will gradually dry up, resulting in decreased capacity, until there is no electricity capacity and failure to present open circuit, loss of filtering effect. Tantalum capacitor is recommended to extend life. We are high quality suppliers, our products such as electric range cookers Manufacturer , kitchen pressure cooker Manufacturer for oversee buyer. To know more, please visits electric pressure cookers.
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