It is either a bad power supply... Most Likely... OR a bad FFC Cable.... The pins don't normally short but the thin copper will crack and not pass power....
And there is no chance that you have a 18 pin cable plugged into a 14 pin circuit board?
Remember the first FFC Cables were 18 thinner pins.... OR you placed a new 14 pin FFC Cable in a old 18 pin Socket Shorting out the power supply... I don't remember if you did any part swapping.... FFC Cable?
Listed as a 16 pin but is really 18 pins.
AL