[iMac8,1, Realtek ALC889A, Green Headphone Out, Rear] No sound at all

[david]

sound through built in speakers but not through headphone jack

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: alsa-base 1.0.25+dfsg-0ubuntu5
ProcVersionSignature: Ubuntu 4.15.0-23.25-generic 4.15.18
Uname: Linux 4.15.0-23-generic x86_64
ApportVersion: 2.20.9-0ubuntu7.2
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: david 1850 F.... pulseaudio
CurrentDesktop: ubuntu:GNOME
Date: Sun Jun 24 23:14:11 2018
InstallationDate: Installed on 2018-06-07 (17 days ago)
InstallationMedia: Ubuntu 18.04 LTS "Bionic Beaver" - Release amd64 (20180426)
PackageArchitecture: all
ProcEnviron:
 TERM=xterm-256color
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: alsa-driver
Symptom: audio
Symptom_AlsaPlaybackTest: ALSA playback test through plughw:Intel successful
Symptom_Card: Built-in Audio - HDA Intel
Symptom_DevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: gdm 1143 F.... pulseaudio
                      david 1850 F.... pulseaudio
Symptom_Jack: Green Headphone Out, Rear
Symptom_PulsePlaybackTest: PulseAudio playback test successful
Symptom_Type: No sound at all
Title: [iMac8,1, Realtek ALC889A, Green Headphone Out, Rear] No sound at all
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 02/09/08
dmi.bios.vendor: Apple Inc.
dmi.bios.version: IM81.88Z.00C1.B00.0802091538
dmi.board.asset.tag: Base Board Asset Tag
dmi.board.name: Mac-F226BEC8
dmi.board.vendor: Apple Inc.
dmi.board.version: PVT
dmi.chassis.asset.tag: Asset Tag#
dmi.chassis.type: 13
dmi.chassis.vendor: Apple Inc.
dmi.chassis.version: Mac-F226BEC8
dmi.modalias: dmi:bvnAppleInc.:bvrIM81.88Z.00C1.B00.0802091538:bd02/09/08:svnAppleInc.:pniMac8,1:pvr1.0:rvnAppleInc.:rnMac-F226BEC8:rvrPVT:cvnAppleInc.:ct13:cvrMac-F226BEC8:
dmi.product.family: Mac
dmi.product.name: iMac8,1
dmi.product.version: 1.0
dmi.sys.vendor: Apple Inc.