Logitech Z906 Amp testing

[jormy299]

Hi all;

Bought the set a few weeks ago and the thing was working intermitently, and eventually stopped working.
Looked inside and came out to the conclusion the PSU was at fault. (Transformer was making weird sounds and no voltage coming out to the amp)
Found some info on here about guys replacing with an alternative power supplies, which I did.

I have a 400w chinese power supply set at 40V connected to the +HV leads
And then 3 buck converters to make the 12v, 5v, and 3,3v (first pin of small connector)
All negative connected together, and connected to GND pins, and second pin of small connector (the 3,3v one)
Everything is connected, console works perfectly (which it did not before) but I still have no sound comin out of any speakers, even using the speaker test mode.

Are there any test points I should check on the amp board to go further into my troubleshooting ?
I truly hoped this was gonna fix my issue, and I have a feeling I'm real close to success.... but there's something I am missing apparently

TIA

[jormy299]

I can provide pictures of the amp itself if that may help....