ATX Power Supply Repair Example (Repost)
Fault Phenomenon One: No DC voltage output after controlled start.
Example 1: The switch-mode power supply was burned and cracked, blackened. Testing revealed that the BD1 to BD4 rectifier diodes were faulty. Additionally, the Q15 switching transistor, ZD8 zener diode, D30 and D41 diodes in the power circuit were short-circuited due to breakdown. The current-limiting resistor R72 was found to be open-circuited.