Problems with the lcd screen after changing motherboard /charging port

Hello, i recently changed the motherboard and charging port on samsung galaxy s4 I337.

The phone will charge, but it will cut off, freeze up. Grey/ red vertical lines, on random screens, grey horizontal lines on logo screen, with freezing up.

So I put the the original motherboard back in the phone, it seems to be ok??

The reason for the swap, i broke the lcd digitizer screen bought a complete phone, issue, won't charge. But I wanted my motherboard not there's. Oh, it's my original charging port.

Please help,getting frustrated fast

Bit of an update... I put the original motherboard back in the phone.

WORKING PERFECTLY.

Done a little UTUBE watching, the best I can can figure the power button needs replacing, only problem, I'm not that good at soldering on other people's stuff.

Any ideas on how to get the best results without the need for solder??