Don't Break It! Easier said than done I know, but it suggests a certain caution when disassembling and reassembling systems and components. You should have a basic amount of knowledge about the configuration and hazards before attempting to disassemble and troubleshoot any system. The general rule of thumb is if a diagnostic test can be done without damage to the unit....do it.
If a system schematic is available, be sure to have that in hand before beginning the troubleshooting process. If no schematic is available, it may be a good starting point to develop some rough sketch. This will help you logically understand the components for the system, and will assist in re-assembly if necessary.