SlideView VS200 slide viewer,
A broken fuse inside the laser that was caused by a short circuit at PIN 4 of the DOOR CTRL. This short circuit was caused by a badly positioned cable that made contact with the housing/frame and caused a short circuit and destroyed the fuse in the laser. This caused the shutter to remain in its most recent state; either in an open or closed position. Once the fuse was destroyed the shutter could not be operated.
US
https://www.accessdata.fda.gov/scripts/ires/index.cfm?Product=Z-2416-2024