Insert the probe into the device, press the button, receive the result - such a smooth laboratory routine with HPLC devices is rare. Often, it is the small details that lead to disruptions, and not always does customer service need to be called immediately. Those who know which parts can be adjusted and which cannot can resolve minor issues themselves - easily, quickly, and without significant costs. Drawing on thirty years of service experience, the HPLC technician guides users through the assembly and functionality of their device, intentionally avoiding theoretical overload. Instead, valuable tips that cannot be found in the manufacturers' manuals show how to identify and eliminate sources of error. From practice for practice - for all those who like to take matters into their own hands when the HPLC device is not functioning properly.