Ignition cylinder switch issue?

Hello everyone im having a issue with my ignition lock at the steering wheel, according to my father who had the issue wheb he owned the vehicle, a mechanic replaced the lock cylinder and lost some spring inside the assembly. So what is happening is if I install the ignition switch it will not turn when i turn the key but if i remove it and turn it with a screw driver I can turn the car on no problem.does anyone kbow what the part is thatbis missing?

Thanks in advance