The other day I started imaging, when all of a sudden I could not see any image on the screen; nor through the ocular.
Immediately I noticed that clicking the shutter button does not make the unique sound of the shutter opening.
I called for help and here is what I learned:
The shutter is controlled by an electronic box sitting on the shelf. The LED light indicating shutter opening was on. Changing the port of the fluorescent shutter to that of the transmitted light shutter did not help. Crossing the cables of the two shutters indicated that the problem is not the electronics or the cable since the shutter for the transmitted light worked fine with the port & cable of the other shutter.
So, the problem was the shutter itself. We dismantled it and indeed, the flaps of the shutter were stuck. No way to fix that easily. What we did was to replace the broken shutter with that of the transmitted light. So we can’t use transmitted light, but can still have fluorescent imaging.
A few points about our shutter:
It was costume built so that on the back side (the one pointing towards the light source) is coated with zinc. This was done in order to reflect the light when the shutter is closed, to prevent over- heating.
On top of that, there is a gap of ~half centimeter in the shutter housing, to allow air flow, again to prevent over-heating.
I found the experience annoying yet educating.