trying to learn from a mistake

hey guys, I've been reading the board and learning how to install hvac stuff for a few months on a derelict farm I bought. Getting better but I made a lot of mistakes in the beginning and didn't have proper equipment, etc. Early on I installed a single 18K Senville mini split from amazon and a few weeks later it stopped working. Didn't diagnose or fix it until a few days ago--the pcb board in the outdoor compressor failed, I swapped it, everything works now. As I was pumping the refrigerant down into the compressor to move that unit somewhere else I noticed I had barely opened the valves to let the refrigerant into the system after the initial vacuum. Obviously that's dumb and that must it created a restriction that made the unit fail, but the compressor is fine, it's just the pcb. There's nothing visible on the board. Any idea what could have caused it to fail in that case aside from my stupidity?