[PROBLEM] No audio after 7.4

[Tim Curtis]

You have to specify the card number otherwise amixer defaults to card 0.

Below is an example of amixer output for cards 0 and 1 on a bare Pi 4. If a USB device were plugged in and powered up  it would be assigned ALSA card 2. so the command would be amixer -c2.

Code:

pi@rp1:~ $ amixer -c0
Simple mixer control 'HDMI',0
 Capabilities: pvolume pvolume-joined pswitch pswitch-joined
 Playback channels: Mono
 Limits: Playback -10239 - 400
 Mono: Playback -4543 [54%] [-45.43dB] [on]

pi@rp1:~ $ amixer -c1
Simple mixer control 'Headphone',0
 Capabilities: pvolume pvolume-joined pswitch pswitch-joined
 Playback channels: Mono
 Limits: Playback -10239 - 400
 Mono: Playback -4543 [54%] [-45.43dB] [on]
pi@rp1:~ $