SHOWA IZ, Unlocking the entrance door due to cylinder malfunction and replacement and repair

"I have the key, but the front door won't open."

It seems to be a regular detached house, but the front door cannot be opened even though there is a key.It seems that the inner cylinder of the knob cylinder is incorrectly positioned.The key has come out in a place where it should not come out. Unlocking the entrance door is possible, but it seems that the cylinder needs to be replaced.

However, the movement of the latch bolt is unstable.There was a problem where the latch bolt was retracted and would not come out.Perhaps the spring is damaged.I decided to disassemble it and take a look at whether to replace or repair the main body case.

The springs that return the latch bolts inside the two springs were completely damaged.It seems that replacing only this spring will improve the problem, so I replaced only the cylinder without replacing the lock case itself.

Due to cost considerations, the replacement knob was ALPHA 33KN.