Did you know that the early #StarTrek TNG "Mark VI" tricorder props, used in the first two seasons, had mechanical latches to keep the lower door shut?

These were removed with the "Mark VII" versions introduced in TNG's third season.

In this fan-built replica, the 'switch' is pulled towards the user while the door is the 'open' position, exposing a metal tab.

When the original prop was in the 'closed' position, the metal tab fit into the slot in the upper portion of the tricorder to keep the door shut.

The Type VII science tricorder in action. ("Emergence")

The Type VII medical tricorder in action. ("The Chase")

A Type VII science tricorder being activated by remote. ("Timescape")

The Type VI science tricorder in action. ("Contagion")

The visible wiring of the Mart VI medical tricorder prop, along with the small band used to open the door when the side latch is released.

....and the door slowly opening after being unlatched. ("Angel One")

Like the more-popular Mark VII edition, the Mark VI medical tricorder also housed a hand scanner in its upper section. ("Shades of Gray")

Data uses an unusual tricorder in "Birthright" -- the device is labeled as a Mark VI and holds a Mark VI-style hand scanner, but the body and labeling is the shape and coloring of the Mark VII.

This odd hybrid design also seems to have been used for the Voyager red tricorders, mounted on the walls of sickbay during the first season of the show.

The Mark VI (early years) version had the medical part as a clip-on attachment. The Mark VII science and medical were two different props. https://twitter.com/DrForester/status/1264359498614894593