Sansui AU-7900 Integrated Amplifier Repair - No Sound Output

This is a video about how I troubleshoot and repair a typical OCL integrated amplifier. Generally, I will test the pre-amp and power amp separably in order to isolate the problem. In power amp, I always check DC offset (amp output) first. it helps finding the problem whether coming from speaker relay or amp output. The best method is to measure the voltage at each transistor. This will tell you that if the power supply correctly feeds to transistor. Once you know there is a problem in the power supply, you can trace voltage at power regulator or the components where connect to the transistors. AU-7900 was designed without DC offset adjustment. So it's output shall stay close to 0V when the components work properly. I hope this video can help other DIY fans troubleshoot and repair their integrated amplifiers.