LM393 comparator is not working
Okay, so you appear to have a time constant of about 2 microseconds on the output.
If  your pullup is actually 10K, that implies a capacitance of about 200pF, which seems a bit high even including your scope probe (use the x10 probe setting to minimize loading).
Check that the resistor is actually 10K and not, say, 100K.
Edit: It is very hard to read the pin names on  your schematic. It appears you have COM connected to Vss but not grounded!
Also, this is not causing your problem, but you should not let the inputs float on the CMOS hex inverter.