Audio issue with connecting PC to TV and using 5.1 speakers

[Buildop]

I am trying to set up a TV (Logik l39fe12) and 5.1 surround (Logitech z506) from my PC.
I have connected from my PC to the TV via HDMI from my graphics card to HDMI on the TV - Visuals are all good!
I have set up the Logitech speakers by connecting all the speakers to the subwoofer, and then the subwoofer to my headphone outlet jack on my PC.
This all seems to work ok when connected up this way with a PC monitor, but when connected to the TV the sound only works from the TV speakers themselves, not the Logitech speakers (although I have heard them from the speakers for very short bursts, its almost like the two sound outputs from speakers and TV via HDMI are fighting one another!)
Here is a schematic of the setup https://ibb.co/j6Bw8Zf
Would really appreciate some help and advice from the community.
Thanks

Note, the speakers and TV manuals can be found at the links below:
Speakers manual (https://www.logitech.com/assets/330...9ifYNMJlGa-cwaf9C5akyOP_-xDRaFCa5zjvM5sxJ2fCO)
TV manual (https://www.buyspares.co.uk/images/mediator/245/Logik L39FE12 IB.pdf)

 

[hornetstinger]

TV to pc could be some kind of feedback loop issue?

I'd send audio from your pc to the TV (which carries audio and video) then ideally line out analogue from TV into spepakers. If not that then headphones out, you'll probably need to set output from TV around 60% or so so not overdrive the input on the Logitech speakers.

 

[AK-47]

Use 3.5mm cables x3 (see diagram below!)
Go from the orange, black and green from the PC to the Logitech Sub
Mute the TV or volume down to zero
On the PC - Right click on the speaker icon in the taskbar (somewhere near the clock on the taskbar) and left click SOUNDS
On the Sound(s) tab that opens left click PLAYBACK
Right Click on the HDMI output - should be marked 'Digital Audio [HDMI] - Then left click 'DISABLE'
Right Click on the Speakers output - should be marked something like 'REALTEK High Definition Audio - Then left click 'SET AS DEFAULT DEVICE'
Click APPLY at the bottom of the Sounds Tab
Right Click on the same Speakers output - should be marked something like 'REALTEK High Definition Audio - Then left click 'CONFIGURE SPEAKERS'
Set the Speakers to 5.1 (Dolby Digital or AC3 or suchlike)
Left Click Apply and then OK
try that

CAPITALS are my emphasis and may not appear on your PC in Capitals!