18.04 loudspeaker not working headphones ok

[sr123456789]

Upgraded from 16.04 LTS to 18.04 LTS main speaker output no longer works. headphone socket on front of PC works ok.

Tried the tips in #1770429 with no effect.

Clean install with format, with no options or changes implemented.

I tried to compile the latest alsa driver from the alsa project but the system objected with 'patch not installed' even it was installed.....

The system is:

Manufacturer: NOVATECH LTD
Product Name: PC-X002115
Product Version: V1.0
Firmware Version: F8
Board Vendor: Gigabyte Technology Co., Ltd.
Board Name: Z97M-D3H

Description: Ubuntu 18.04.1 LTS
Release: 18.04

Kernel release: 4.15.0-32-generic
Operating System: GNU/Linux
Architecture: x86_64
Processor: x86_64
SMP Enabled: Yes

!!ALSA Version
!!------------

Driver version: k4.15.0-32-generic
Library version: 1.1.3
Utilities version: 1.1.3

with a 128G SSD and 1T HDD.