To reassemble, first fit the geared section to the outermost section, ensuring that the pips in the flash head actuator are engaged in the grooves in the geared section.

Turn the geared section fully clockwise within the outermost section and insert the inner sections with the screw holes lining up. Two pegs in the outermost section, one adjacent to the motor and the other almost diametrically opposite, should line up with their holes in the flange.

If necessary, rotate the gear teeth by no more than one or two teeth in order to get it to fit. Expect to have to do a bit of fiddling and to try several times before it goes together. No force is needed.

Temporarily insert one of the 4 screws to hold it together while you extend the lens in order to feed the ribbons through their slot. Close the lens again before fitting the back plate.