speakers not working on alienware 15 r3

I bought this laptop 3 months ago,

AW15R3-7002SLV-PUS    windows 10

I had so many problems with it:

after a week  the laptop stooped working, so dell replaced the motherboard.

then after 4 days the speakers and 3 keys from the keyboard stooped working, so dell replaced the speakers and keyboard.

But the speakers still not working,

No Sound from speakers but the headphones work fine on windows 10,

sometimes the speakers do work but after a restart they stop working.

In f12 mode (ePSA test) the speaker test is not working (no beep sound)

I Update all the drivers including the bios.