That night, Leo desoldered a swollen 2200µF capacitor near the heat sink. The board was discolored—brown and angry. According to the manual’s "Thermal Event Log" (a section he’d never seen before), the Z906 had a silent kill switch: if the main power rail exceeded 85°C for more than 30 seconds, it would slowly cook its own audio processor.
The air in the workshop was thick with the scent of ozone and burnt flux. logitech z906 service manual hot