Non responsive 17in Powerbook after replacing DC board

First post from a long time lurker.

Last week I replaced my fried DC board on my 17in Powerbook model A1085 after living with a testy connection for years. I had no problems with disassembly or reassembly, yet the computer will not turn on now. I have checked everything many times, and nothing is out of place.

The DC board seems to be working fine; lighting up the charger cable and charging the battery. The computer even seemed to turn itself on at one point as I could hear the hard drive spinning, but nothing else, no screen or response from pressing the power button.

I thought it could be a top case connection issue, but there is no damage to anything and its connection seems to be sound.

I was recommended to touch two points on the logic board that would power the computer on without the top case, but I'm afraid of further injuring the computer by touching the wrong points.

If anyone has any advice on how to approach the device to find the problem, I would be grateful. I'm not in a financial place to bring it in for repairs, so I would like to do any work myself.