Stefan Zambinski: Evoke 1200B FL-35YK lens repair

As part of my role as Technical support for the Masters Degree in Filmmaking I often make minor repairs to equipment. Just recently one of our Nanlux Evoke 1200B lights was returned from a student film shoot and during the check in process I noticed the focus ring on the fresnel lens (FL-35YK lens) was sticking at around 18 degrees (the lens has a beam angle of 11-45 degrees). On initial inspection - you can undo the focus range dial to reveal the mechanism - there was no obvious obstruction and certainly no signs of damage. I thought this is odd and the item will need to go off for specialised repair. However I then put the item to one side. Today I made the decision, under controlled conditions and giving myself time, to fully open the fresnel mechanism. I paid careful attention to the positions of the dials, rings and mechanics of the device by marking the parts with tape. This was so that I would know how to put it back together after. I had to remove the threaded rods that enable the Bowens mount to move backwards and forwards to then allow the Bowens mount to move freely and reveal the issue. On close inspection of the internal area I noticed two of the six screws that hold the yolk on the sides of the unit had come loose and where obstructing the mechanism from passing. I tightened the two loose screws and checked the opposite side was also fully fastened. Assembling the mechanism again was easy because I had placed tape on areas that needed to be realigned. The focus ring now turned freely and the full range of the lens' beam angle is now restored.