Dry Joints In Surrounding/Corresponding Components
Do you know that there are many cases of electronic problems were caused by dry joints in the corresponding components? Yes that means if you found a component or few components that have problem, please don’t just replace the component/s and retest the set. There are chances the component/s that you have just replaced could fail again. This would surely waste your valuable time and money. In order to solve electronic problem, one has to make sure that the corresponding components are okay before you replace the bad components and retest the set again. Sometimes even if the equipment did not breakdown at that time it may breakdown few days later.
Unless you have already know the common fault of the equipment then you may skip to check for dry joints in other section. In certain cases for example a dry joints in the flyback transformer pins may cause HOT to short circuit and the end result the B+ circuit components also suffered from it. That means it is not necessary to look for dry joints in nearby section, you should also check something that is located downstream the line.
To some repair technicians, they will take extra precaution by applying fresh solder to some suspected points even though the solder joints looks good. This will prevent callback from customer. That day came in a Dell LCD Monitor for repair and the complaint was intermittent shutdown. Just by normal scanning the board you could hardly see dry joint but when i took out the magnifying glass i could see very tiny mild cracks around the solder in the high voltage transformer pins. Resoldering the joints solved the intermittent shut down problem.
Conclusion- To prevent call back from the customer, make sure you have check all the surrounding/corresponding components.