Hello all I have an MSI B550M Mortar motherboard which has Realtek ALC1200 onboard audio. Currently running Windows 7 x64. I'm trying to use the S/PDIF optical output with Logitech speakers but I'm not getting any sound output at all no matter what formats I test, or what settings I apply. Additionally, I only see options for "2 channel" output formats whereas there should be 5.1 channel options too. The speakers and optical cable are confirmed working with my old motherboard's onboard audio. The Hardware Ids of the MSI B550M's ALC1200 audio device are: HDAUDIO\FUNC_01&VEN_10EC&DEV_0B00&SUBSYS_1462EC94&REV_1000 HDAUDIO\FUNC_01&VEN_10EC&DEV_0B00&SUBSYS_1462EC94 Things I have already tried: Latest "Univeral" Realtek audio drivers from their site (R2.82) Older Realtek drivers which worked with an Asus motherboard (R2.80) Drivers from a different MSI motherboard with similar onboard audio for Windows 7 (driver v18.104.22.16819) Drivers from a totally different mobo (Asrock) which uses the same chip as mine (driver v6.0.9132.1) -- in this case, the driver package contains the exact same hardware ID string as mine so it *should* definitely be compatible An extremely helpful driver modder has been trying to help me on a Techpowerup forum thread but so far I've had no success. I discovered a discussion thread about the ALC1200 on this forum from 2008 (!) so I thought I would ask here as well because people here seem very knowledgeable. I'll try anything at this stage - I've wasted a whole day trying to make this work. Any suggestions are very welcome. Thanks.