What is the raw DC input voltage and op-amp rail voltages? I would first get CV mode working but building something like this is always a lot of fun learning.
Input DC voltage = 29.0V with load at the output 32.4V without load at the output
Op-amp rail voltages = 28.6V with load at the output and 29.4V without load at the output
Without load, the output voltage varies from the potentiometer from 0V to 25.5V.
The output current varies from the potentiometer from 0A to about 3.3A if I first go with the potentiometer to 0A and then I go with the potentiometer to 3.3A, while the ammeter is connected to the output.
If I set the current limit to maximum, and then if I connect the ammeter it shows about 2.40A, and the led does not lit.
What else should I measure to determine were is the problem ?
Later Edit: I found that if I connect the load and after connecting the load I plug the power supply to the 230V, then the output voltage does not drop. This happens only sometimes. But if I connect the load after I plug the power supply to the 230V, then the output voltage drops from 25.5V to about 19-20V.
When the output voltage drops to 19-20V, the voltage on BC337 from the original schematic collector is about 28V.
An alternative way could be a NPN transistor turning on with more than 0.6 V over the shunt and pulling down the base of T1.
Should the attached schematic work ?
I also made a simulation... but I am not sure if the simulation is correct.