iMac Not turning on, LED 1 present. Changed so many components

I think I really hit a road block.

It started with not turning on with LED 1 present.

I changed Power Supply (checked that it works with another machine) but same LED 1 only.

Changed Logic Board (checked that it works with another machine) but same LED 1 only.

Changed DC harness, same LED 1 only.

Checked power button and tried the connecting two-pins. Nothing. Same steady LED 1. I even tried to cross connect with another iMac (put two iMac A & B face to face up close and connected the A’s power supply to B’s logic board) to see AC cable plug in the back is faulty. It’s working fine.

…I think at this point, I literally built a new iMAC with different components.

One part I have not yet changed was CPU, but can bad CPU cause LED 1 light and not turning on (no chime, no fan etc)? I read so many posts on this site and almost all of them were either power supply, logic board or even power button.

I can really use some help right now…