PSpice OrCAD Adding Diode and Unknown Source
This is my interpretation of your question. I might be tackling this the wrong way.

I think you've got some circuits around a diode and you want to find what the input voltage has to be for the diode voltage to be 700mV. I just tried a simple series resistor and diode.

I drew the circuit in Orcad Capture and didn't specify the voltage on the source:



Then I set up a simulation profile to sweep the voltage source over a range of voltages:



Finally, I plotted the voltage across the diode and used the cursor to find where the diode voltage was 700mV. I found that V1 = 1.88V at this point.



Maybe you can take this idea and apply it to whatever circuits you're analyzing.