Whatever soap your using is there to dissolve and/or loosen the "dirt". There is usually a mechanical (friction) action needed to clean something properly. Too much soap lessens the friction. At a certain level of saturation the soap begins to act like a lubricant. This amount varies depending on what your using. For most cleaners I use 10-20%.
Choosing the right type of cleaner is key. This guy can explain it better than me.

YAY SCIENCE!!

If your pic is after the "pop" you still have lights and power. It may have been a mechanical noise. I'd look at the bottom of the inner tub where the ultrasonic "generator"(?) is mounted. Maybe it came off. Or you may see signs of water giving you a clue. If your going to toss it anyways what could it hurt? The one thing this thread doesn't have is Ultrasonic innerds pics.

Bottom pic, top right hand component on the board is a soldered on fuse. It looks a little dark. Maybe you get lucky and that's it. Make sure it's very dry before powering back up.m

Even if you decide to tumble them you should US clean them first. I put anything that will fit in mine