This is driving me potty. I have probably made things worse by following every solution I can find 
System: Host: xircon-w6567sz Kernel: 5.10.3-arch1-1 x86_64 bits: 64 Desktop: KDE Plasma 5.20.4
Distro: EndeavourOS
Machine: Type: Laptop System: Notebook product: W65_67SZ v: N/A serial: <superuser required>
Mobo: Notebook model: W65_67SZ serial: <superuser required> UEFI: American Megatrends v: 1.03.05
date: 02/26/2014
Audio: Device-1: Intel Xeon E3-1200 v3/4th Gen Core Processor HD Audio driver: snd_hda_intel
Device-2: Intel 8 Series/C220 Series High Definition Audio driver: snd_hda_intel
Sound Server: ALSA v: k5.10.3-arch1-1
aplay -l
**** List of PLAYBACK Hardware Devices ****
card 0: PCH [HDA Intel PCH], device 0: VT1802 Analog [VT1802 Analog]
Subdevices: 1/1
Subdevice #0: subdevice #0
card 0: PCH [HDA Intel PCH], device 2: VT1802 Alt Analog [VT1802 Alt Analog]
Subdevices: 1/1
Subdevice #0: subdevice #0
card 1: HDMI [HDA Intel HDMI], device 3: HDMI 0 [HDMI 0]
Subdevices: 1/1
Subdevice #0: subdevice #0
card 1: HDMI [HDA Intel HDMI], device 7: HDMI 1 [HDMI 1]
Subdevices: 1/1
Subdevice #0: subdevice #0
card 1: HDMI [HDA Intel HDMI], device 8: HDMI 2 [HDMI 2]
Subdevices: 1/1
Subdevice #0: subdevice #0
card 1: HDMI [HDA Intel HDMI], device 9: HDMI 3 [HDMI 3]
Subdevices: 1/1
Subdevice #0: subdevice #0
card 1: HDMI [HDA Intel HDMI], device 10: HDMI 4 [HDMI 4]
Subdevices: 1/1
Subdevice #0: subdevice #0
cat /etc/modprobe.d/alsa-base.conf
options snd slots=snd_hda_intel
options snd_hda_intel power_save=0
# Intel PCH
options snd-hda-intel index=0 model=auto vid=8086 pid=9c20
# Intel HDMI
options snd-hda-intel index=1 model=auto vid=8086 pid=0a0c
Sound is patchy on 5.9, sometimes have to reboot several times. Sound is non-existent on 5.10.
Have rolled back to the 28th and have sound at the moment, but it may not survive a reboot 
Any ideas? I can see posts on the Manjaro forum with the same problem and no solution.