Mount the new resistors with a slight air gap from the PCB and capacitors to improve airflow. Remove any "black rubber" or glue around them, as it can become conductive after years of heat cycling. Logitech Subwoofer Z906 Power Supply repair part 2
: If the system is completely unresponsive, inspect the internal fuse located near the power input. Logitech z906 power supply board REPAIR - EEVblog logitech z906 service manual patched