A little technology
Repair is a profession...
It's also a passion
This page has only one purpose: to explain a repair procedure.
I decline all responsibility if you break your beautiful toys... That's it!
Basic method
Overall, the procedure is always more or less the same after changing the curtains, regardless of the brand of the device.
The main difference is the type of tensioner and the necessary tool.
For a precise adjustment of the translation speeds of the curtains, the use of a shutter tester is essential.
It will allow to obtain accurate and reliable values, in the majority of cases, it is +/-12 ms.
Then, comes the adjustment of the shutter speeds (that’s another adventure).
Each brand has a specificity for adjusting the speeds, fast and slow.
The biggest mistake in the event of a shutter malfunction is to “tighten” the curtains.
Indeed, each of them must move at the same speed or as similar as possible.
Reflection: It is important to understand that the shutter is a slot between the curtains that covers the format,
which fully justifies that the scrolling speed must be identical during the journey in front of the window.
This slit is narrow for fast speeds and wider for slow speeds.
(except for slow speeds dependent on the mechanical module… slow speeds of course)
A shift between the curtains, by too much or not enough tension will inevitably cause an error in the illumination of the film.
Imagine: (slow motion action…)
You trigger, the first curtain starts, a time X is selected by the speed selector, which determines the width of the slit. (Here we are in the domain of the space / time relationship)
The second curtain is released and together, they travel the exposure window, but the second curtain is out of adjustment (too much tension for example) halfway through, the second curtain has already caught up with the first by 40% then, at the end of the shutter, by 70%
if it is not 100% halfway through, which results in half-exposed negatives.
When adjusting, it is imperative to use a shutter tester with 3 measuring diodes.
The acceptable tolerance must also be taken into account.
