Abstract: At the beginning of the mass production of the power modules, the immature production process may lead to a higher failure rate. To counter two failure phenomenons of "no voltage output" and "abnormal load startup", the root causes of the problems was found out, the tooling and fixture for electrical regulation were designed and applied, the electrical regulation and welding process requirements were pefected, changing the encapsulating material and taking the circuit protective measures before encapsulating greatly reduced the failure rate of the power modules and improved the reliability of electronic products.