Asrock x370 taichi can't detect onboard sound 1220

Dear Asrock TSD:
I've Built a PC with x370 taichi,The PC spec as below, But it can't detected the onboard Realtek ALC1220 sound card, It can't find the device in device manager even if I selected show the hide device.I fined the After sales service supporter,They try to use change another motherboard and test the motherboard in minimum system environment,it can works on the test machine(GTX240 and low profile cpu),But when I try to install the motherboard on my PC, it can't works.
Also I try to fix the problem.
I try to replace the Graphics and memory power supply but the problem still.
I try to downgrade to 2.0 and upgrade to up to now Bios version(use the bridge bios)
I try to remove the battery and clean cmos and resume the default setting many times.
I try to reinstall the OS,include try to clean ubuntu centos windows10 windows8
I try to replace the memory
But problem Still,The system can not detect the onboard sound card hardware
I hope Asrock TS can help me fix the problem,Since I do my best and contact the native TS many times but they can't help me.
Sorry for my poor english, my native language isnot english
My PC spec:
CPU：AMD Ryzen 7 1700x
Memory: 16G corsair DDR2600 + 4G Samsung 2600 OC 3000Mhz （Dual channel�
MotherBoard:Asrock X370 Taichi
PowerSupply:BUBALUS 700W Gold Label
Graphics:Nvidia 780Ti 3G
        For test bought new graphics card: SAPPHIRE Vega 56 8G
Harddesk Seagate 3TB
Thank you very much!