Changed Battery and Mainboard - Charges, firmware - Won't turn on

I have repaired some powerbeats v2, by happen stance i had 2 pairs

1 - had gone through the laundry and was water damaged

2 - wiring was damaged from abuse

I did a transplant

Good battery from wire damaged to water damaged

good mainboard from wire damaged to water damaged

After the repair I plugged them in and the software detects them, it even let me update their firmware. Before updating I attempted once they were charged to 30% to power them on...this didn't work

I have since tried at full charge, i've updated the firmware, i've plugged them in and completed a factory reset (Power button & Volume Down for 10 seconds) . They flash and do the reset but once off power they again will not turn on.

Any ideas?