彩电维修--------伴音故障（TV maintenance Sound Fault）.doc

彩电维修--------伴音故障（TV maintenance Sound Fault） TV maintenance: Sound Fault (2007-11-05 09:04:08) Tags: knowledge / exploration 1. no sound troubleshooting (1) fault phenomenon When receiving color broadcasting, the color images reproduced on the screen are normal, but the sound is not heard from the speaker. The tone and the + key are still invalid by re tuning and pressing the audio. (2) fault analysis In the integrated circuit of color TV, because the low level of linear synchronous detector, between color subcarrier and sound signal detection circuit generates the 2.07MHz beat interference is reduced, so it can be a positive image, color and sound signal, by put in integrated circuit video output from the three signal. It is no fault of normal sound color usually involve the entire audio channel and additional power supply and control circuit. (3) overhaul method When there is no sound failure, the following methods can be adopted: Distinguish the fault parts with the method of human induction. When holding the metal tool forward followed by striking the sound channel of each key point, if the strike to hum a point in the speaker will disappear, fault circuit after the key points in the. Disconnect the squelch circuit to judge whether it disappeared and fault. If you disconnect the squelch circuit, sound is normal, indicating a fault in the squelch circuit; otherwise, has nothing to do with the squelch circuit. With oscilloscope along the signal process to detect waveform, it is easy to find where the signal is interrupted, can quickly find fault. Detect faults with voltage and resistance detection. DC voltage detection can detect power supplies, faults in integrated circuits and transistors. Resistance check method can detect faults. DC voltage detection can detect power supplies, faults in integrated circuits and transistors. The resistance check method can find fault components such as open circuit of potentiometer, open circuit breaker or bad contact of plug. I