My Samsung front-load washer (model #WF50K7500AE) stops; sometimes during the wash cycle, sometimes during rinse, sometimes during spin. Oftentimes the door will unlock for the "add clothes" feature but then won't re-lock and resume. I have to push the start button...and sometimes that won't work. It just sits idle. I replaced the water level sensor after reading an online post. Didn't help. I'm thinking the next step is the control board but that's a pricey bet. Big family (five kids) so the washer runs every day. I'm tempted to just buy another but this one is only four-years old. Ideas?