Switch Backlight turns on immediatly after plugging the battery

Recently bought a pair of NSwitch for parts. Both had shorted ports and blown PI3USB.
One has a deff dead short on the CPU.
The other managed to turn on after removing both the charging port and PI3USB.

Ordered BQ, PI3 and M92 replacements, replaced both M92 and BQ. (PI and charging ports are both still unpopulated)
Now the console won’t turn on at all. As soon as I plug the battery the backlight will turn on at full brightness. Will stay on until I press power but nothing else will happen.

Any ideas of what I should check?
Already used 3 of both M92 and BQ + a pair of known working from a working unit and same results.