That was it. The circuit was just fine. The Tek 2445 scope was set to
50 Ohm input and was screwing up the signal, in effect swamping the little pull down voltage with its 50 Ohm resistance. I switched it to 1 Megohm and everything works great!On these photos you can see different duty cycles (percentage of positive and negative in every pulse) and the assembled circuit.
You can see how transition from negative to positive -- the wave -- is not quite square. No worry, I hope that the comparator chip will take care of it.
Here are pix of the waveforms and the scope etc.
I will try to do a few things now. One is to assemble a switcher for changing frequency (variable capacitance), being mindful that I cannot allow zero capacitance during switching. I have a 11 position switch for that.
Another is to add a comparator chip, so that I have signal for both the high and low side switches (opposite signal). Should be no big deal. I am extremely happy.
i