Troubleshooting Repairing Switch Mode （故障诊断维修开关模式）.pdf

Troubleshooting Repairing Switch Mode Power Supplies Brought to you by Jestine Yong http://www.PowerSupplyRepairG Content Part I Introduction to SMPS 1. Introduction to Switch Mode Power Supplies (SMPS)………..9 2. Identifying Electronic Components in Different Types of SMPS with the Help of Photos…………………………………………14 3. Block Diagram of a Typical SMPS and How It Works………18 4. Easy Way To Understand The 11 Circuit Functions of SMPS With The Help Of Schematic Diagrams………………………24 4.1- Input Protection and EMI Filtering Circuit………26 4.2- Bridge Circuit………………………………………………27 4.3- Start Up and Run DC Circuit…….……………………….29 4.4- Oscillator Circuit…………………………………………..31 4.5- Secondary Output Voltage Circuit…………………34 4.6- Sampling Circuit…………………………………………...36 4.7- Error Detection Circuit……………………………………38 4.8- Feedback Circuit…………………………………………...39 4.9- Protection Circuit ………………………………………….40 4.10- Standby Circuit ……………………………………50 4.11- Power Factor Correction (PFC) Circuit………………...56 5. Electronic Components Found In SMPS and Possible Causes…………………………………….………………62 6. How To Find The Right Equivalent Components In SMPS Circuit……..……………………………………………………..86 Part II Secrets of SMPS Troubleshooting Techniques 7. Recommended Tools and Test Equipment For Successful SMPS Repair………………………………...……….…………95 7.1-Isolation Transformer……………………………………..96 7.2-Variable Transformer……………………………………..98 7.3-AC Ammeter……………………………………………….100 7.4-Analog and Digital Multimeter…………………………...102 7.5-Digital Capacitance Meter………………………………..104 7.6-Blue ESR Meter…………………………………………...105 7.7-Blue Ring Tester…………………………………………..106 7.8-Oscilloscope………………………………………………..107 8. Safety Guidelines………………………………………………109 9. Understand The Six