Some graphic tablet pens stop working properly or get unreliable after some time of usage. First, one should check the most common issues:
If the hints above do not help experienced user may find a solution by disassembling the pen. The following issues may be fixed there:
At disassembly it is often necessary to remove exposed parts like buttons first. Most parts are hold together using snap-in connections and are only to be removed after other parts. A sharp knife is often a handy tool.
Important: Never apply force during disassembly. Avoid getting far into the pen using sharp tools - most components, especially solenoids, are very fine and easily destroyed.