NEWBIE - POWER SUPPLY SIMULATION PROBLEM

[obiwankenobi]

Hello friends, I am a newbie to SPICE nad Micro-Cap.
I need help with this simulation. It is about a 50V @ 10 A power supply.
The original circuit was taken from the National Semiconductor LM723 datasheet.
I added one Darlington and extra power transistors.
The problem is that before going deeper in the simulation, I can see that the D4 Zener diode shows a very high voltage of almost 80 V instead of the rated 36 V.
I tried to lower the output current and I think that leaving the CL and CS terminals of the LM723 is not a good idea for the simulation.
I searched for some specific Micro-Cap forum in Google but no luck.
What am I doing wrong ?

Thank you in advance.

[kaspich]

U drop on D4 is 79.3-45.5 = 33.8V and is OK

1. replace D2 with 100ohm
2. add 1Kohm between B and E of X2
3. add 100ohm between E/X2 and CL/UA723
4. replace R1 with current source
5. replace D4 with 15..20V zener