If it helps explain your issue mine had the same issue before recap. So either a cap may not be connected or backwards. Also if you sent just the motherboard the screen keyboard and the power harness I am sure uni could at least test the unit. The interlock can be closed and just plug in a powerbook 100 series plug and hit a key on the keyboard to boot. that way its not too heavy to ship, doesnt need a mouse, floppy or hard disk to show its working.

Good Luck.