Fault analysis, fault line scanning circuits. According to experience, I use chopsticks by touching the line calls can easily lead to line frequency components in the circuit, especially near the heat sink several components when touching the line inductance L302 linear correction, and calls to stop, remove L302 check the pins loose contact with the coil. Repairing welding treatment, call the fault disappears, but fresh trouble, namely stretch on the left side of the image. Compression on the right. Analysis of the cause of failure, the problem was out of line on a linear regulating inductors L302, remove L302 check without exception, L302, mount, both failed disappeared. Try L302 turn loaded onto another stretch, the image left and right compression symptoms, L302 turn fitted, the fault disappears.

Fault analysis, fault line scanning circuits. According to experience, I use chopsticks by touching the line calls can easily lead to line frequency components in the circuit, especially near the heat sink several components when touching the line inductance L302 linear correction, and calls to stop, remove L302 check the pins loose contact with the coil. Repairing welding treatment, call the fault disappears, but fresh trouble, namely stretch on the left side of the image. Compression on the right. Analysis of the cause of failure, the problem was out of line on a linear regulating inductors L302, remove L302 check without exception, L302, mount, both failed disappeared. Try L302 turn loaded onto another stretch, the image left and right compression symptoms, L302 turn fitted, the fault disappears. Confirmed that the inductance is linearly correction "polarity".