Qisheng AV-737 Power Amplifier Complicated Troubleshooting Two Examples Circuits

Published:2011/8/2 21:46:00 Author:Robert | Keyword: Qisheng, Power Amplifier, Complicated, Troubleshooting, Two, Examples | From:SeekIC

Example 1: the error symptom. A Qisheng AV-737 amplifier is combined with VCD. When it connects the signal wire and plug in the power, the amplifier would enter the standby mode. If the user opens the VCD power firstly and thenopens the amplifier, the amplifier's all functions would be disabled (include remote-control function). When it occurs the crash failures, at this time pressing the AV-737's power plug solely, and plugging in after some seconds, then it would start normally. If each time openning the AV-737 power amplifier power and then openning VCD, it would not have the error above.Analysis and maintenance. When it occurs the faults, the standby power supply is tested to be normal, the CPU1997(or 9800)'s pin 64 and pin 46's 5V power is also tested to be normal, the pin 32 and pin 44 (ground port) are normally connected to the ground. Pressing the power switch button, the CPU's pin 28 (power) control output port has no variety. The AV-737's power switch mode is touch-button control switch. When it is connected, the CPU would receive the starting command and its pin 28 would output high voltage level. Then the control the relay to be closed to make the whole device's power connected.



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