This is a tabletop photodetector interface (D1002932-V5, S1103811) in ISCTEY that was misbehaving yesterday. I opened it and found this.
None of the power connectors for Thorlabs PDs and BBPDs were soldered to the board. And one of the connectors was loose (right-most one in the video). See how the legs move as I wiggle.
It's a miracle that it worked at some point. I soldered all of the connectors.
(If avi doesn't play, try mov file, though the time of the mov file seems to be out of whack.)
I opend and checked two randomly selected "Table-Top" boxes (D1002932-v4) from the twelve boxes in Mid-Y storage, serial numbers S1103796 and S1103810, for quality of build and found them to be in good shape. The front circuit card was soldered onto the panel connectors. All screws and fasteners were tight. The general quality of work looked good. Let's hope the box Keita found (S1103811) was an oversight.