Followed by the poor thermal stability of the component codes, with iron close to the suspect component, and so the power is not working, it can be considered a fault in the component, can be replaced with a new element is determined. If you find that a particular component hot, wet cotton ball can also be used to cool the components, if the power supply is working properly this time, indicating the performance of the components have deteriorated, substitution with new components. 

 

In addition, change the value of R6, C5 open, U2 current transfer characteristic deterioration, lack of capacity C1, could result in the failure.