Fred,
By moving the ground connection from below C1 to below V1, you also need to change your .IC statement, so that the initial voltage is applied across the capacitor:
? ??.ic V(C1node,N002)=0
You don't want to start the simulation with V(C1node)=0 when the other end of C1 is not grounded.? The results are rather bad if left that way.? That's why you got the unexpected results.
Two other suggestions:
It's a Really Good Idea to name the net connected to the bottom of C1, after moving the ground from there to below V1.? By leaving the net unnamed, it inherits the temporary nodename N002, which can change on you if you make other changes to the schematic.
The other thing I recommend is not using the default diode "D".? D is an idealized diode model with zero resistance and capacitance, which are known to sometimes cause simulation problems.? Sometimes it's OK, sometimes not.? Any of the diodes from the "Pick New Diode" menu have realistic values.? The D diode model is the standard one from SPICE, 50 years ago.? As it happens, with the right .IC statement, any diode is good enough; but with the wrong .IC statement AND the "D" diode model, LTspice struggles.
Andy
