Speed is everything with a switching power supply adapter and as time is measured in nanoseconds rather than seconds, it is important to have the adaptor set at the right level. For engineers who are designing an adapter they soon realise that it is not as straightforward as they imagined it would be. To be able to create one that is not only fast but also cost effective and lightweight takes plenty of practice. There are so many possible pit falls that it would be wrong to expect to be able to provide a perfect specimen early on. With practice comes real experience and there may be a few failures before the solutions are found on a regular basis.
Once you have mastered the art of building, or quite likely bought your adapter, there is the chance that there will be a problem at some stage. Two of the main downsides to this form of running an appliance are the noise and the fact that they can overheat very easily. Switch mode power supplies are often built with the parts placed close together and this can cause components to overheat even before the airflow is able to reach them. It is not always easy to identify the failure being in the power supply adapter, as quite often the only information you will have is that the machine will not switch on.
It is paramount that you are careful when dealing with the power supply as there is the risk of getting an electric shock. It will be easy to get an electric shock from either working with the power lead in or working on a machine that has only just been powered up. Some machines wind down quickly but others still draw electricity even when they are turned off. Brown spots are a giveaway sign that the problem is overheating.
On occasions random checks can be made and it is a bit of a case of suck it and see before the real problem is identified. One idea is to replace the electrolytic near to the heat supply and then check resisters and diodes, but it may turn out that these are fine and the machine still does not work. Even once the problem has been solved and the machine is working again, there may be a hint as to what caused the breakdown and you will have an idea of what to look for in case of a further breakdown. For example, if the fan is still noisy, that will not be allowing enough air to flow and will need to be replaced.
Some devices are much more efficient than others, and this will be obvious when you find out how much power you are able to get out of the switching power item you use. It is important to buy one that lets you change the efficiency meaning that one device can be used for powering more than one household appliance. To make sure that your machine is running efficiently and power is not lost, it is important to have a stable output voltage.