Tem uma luz branca sob a borda posterior da placa-mãe que pisca
Isso parece ser a iluminação de LED de áudio :
These LEDs light up when the system is fully powered and operating. To change the behavior of the LEDs to still mode or breathing mode, refer to BIOS section 2.6.8 Onboard Devices Configuration Audio LED Lighting for details
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2.6.8 Onboard Devices Configuration
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Fonte Manual do Z170-E