Turning on A MacBook Pro Retina without the battery installed.

Hello I have a macbook pro a1502. It was given to me by a friend. When I opend it i found one of the cells was bad and the whole battery is bad. I also never got a power adapter for it. We ordered one that claims it works with this model. When the magsafe is plugged in, the light turns orange like it is charging it. I cannot power it on with or without the battery in it. I can reset the SMC but that is all the life I cant get out of it. Does it require a working battery to even power on, or do I have a bad logic board?

Well. Reseating the cable to this I/O board now makes it power up. It will boot but only under one condition. I have to have the internal display unhooked from the logic board. It will boot and work just fine with just an external monitor plugged in. It’ll even boot with out it. It will not if the internal one is plugged in. I have even tried unhooking the display itself from the cable and plugging it into the board just to see if the cable itself is causing it and it still booted. With the display plugged in, I will get the chime then the backlight will come on. On the external display I’ll get the apple logo with a spinning wheel. This will disappear after a few seconds and I get a white screen on the external and a blank screen on the internal one. The caps lock key won’t even light if I press it after a bit. So it makes me think that the display is causing it to halt. Thank you for getting me a bootable mac. Now I have to figure out this problem.