Sony HT-CT290 independent subwoofer wont power on

[Im_Tesla]

I've a 15 month old sony soundbar with independent subwoofer. The subwoofer wont turn on but the soundbar works fine. I've taken apart and did some measurements. Power supply board is producing 18.5V, I think main board has some problems. Can anyone help me what's wrong with the sub unit?

I've attached the measurements.

Second pic is of a component (4WHOVJ20865) which has 18.5V as input but output is 0V. Maybe this component is broken? Can anyone tell me exactly what is this 6 legged component?

https://pasteboard.co/JxKzHXC.jpg

https://pasteboard.co/JxKBmft.jpg

[akimpowerscr]

Always start with the simplest:
have you checked if the coil of your subwoofer speaker is not interrupted?

If not:
https://fr.ifixit.com/R%C3%A9ponses/Afficher/615901/Subwoofer+on+Sony+HT-CT290+sound+bar+not+working

[Im_Tesla]

Thanks a lot for the reply.
I've checked the sub speaker coil is good.
I've gone through the linked post and found that the Ti buck regulator is working fine and producing 3.27V. I think problem is something else.

See my 1st picture, I've mentioned the region that has no voltage. What could be causing that?

[akimpowerscr]

To continue the search for faults, it would be necessary to have the service manual.
Unfortunately, I couldn't find it on the internet.
Maybe you will have more chances than me?

[andy3055]

This site seems to have it but one has to make an account there to see the high res files.

https://servicemanuals.us/sony/audio/ht-ct370.html