If that passes, it’s the power button (unlikely, it’s just a button) or the motherboard or some component. If the power button contacts are exposed, and assuming it’s a regular momentary contact switch, you should be able to bridge them to complete the power button circuit, eliminating the button itself.
ect
*etc., short for et cetera, Latin “and the rest”.
But native speakers do that all the time too. I don’t know how, because nobody ever says “ect” out loud.
Hmm. Like @ganeshaix said, maybe the cable, or the backplane? Does it work if you connect the drives directly to the card?
SAS to 4 times SATA
I’m no expert, but can you do that? Are they SAS or SATA drives? Do they show up if you connect the drives or backplane directly to the motherboard?
No idea. Continue to the next bit.