This step is the actual repair procedure for the shutter error.

The error is caused by a weakened shutter return spring. Due to extensive use it doesn't have the power to close the shutter.

Normally the motor opens the shutter curtain and engages the mechanism with a small neodymium magnet.

When the electromagnet is activated, the neodymium magnet is disabled and the shutter curtain has to travel towards closing direction with the help of the return spring.

However, when the return spring is not strong anymore, it cannot move the curtain.

For repair, using a pair of tweezers, turn the spring adjustment wheel (the black round wheel with teeth, bottom one shown with red arrow) for 2-3 clicks towards the direction of green arrow. Compare the first and the last photo for the amount of rotation, it is only a tiny bit!

This should do it.