Thanks so much. Yes I will check the pressure switch and the hose. I'm assuming that if I can activate the switch by blowing into the hose, all is well. But I will also check the hose for integrity blowing underwater, etc.
In the meantime, how can I tell if the timer/control board is operating properly?
by way of diagnosis: I can also report that sometimes when the tub is not filling, if I turn the timer knob in/off, then on again, it starts working. So maybe you're onto something there...