There is a missing step in those instructions. On systems, with removable batteries, remove the battery after you remove the power cord. On systems with out a removable battery, check with your pc maker on how to do an EC reset. On my MSI GE73, there is a tiny pin hole on tye bottom of the laptop that must be held down for 30 seconds. In both.scenarios, this performs a (embedded controller) reset. If there are no other hardware issues ( like failed hardware), then your system will boot normally and the high definition audio controller will start working again.
I only wish i had found this out back in feb of '19 when i made my first post to this thread. It could have saved me much grief and time.
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