Smoke appeared when my wife was using it so she unplugged it. She said the timer seemed to be ticking as it usually does, but nothing was happening.

I plugged it back in to diagnose it and all we could get it to do was hum. We did get it to add a little more water, but it wouldn't pump it out when we moved the timer to that cycle. I think the humming noise is coming from down inside the main unit. It seems to do it during all the cycles. Anyway, after not taking enough time to properly think about it, I convinced myself the timer must be bad and replaced it. Of course, that's not it.

I hate to junk it out and am quite handy with repairing things but not always good at diagnosing them.

Any suggestions? Thanks in advance for your help.