These ARE vacuum tubes! They have a grid, anode and cathode same as a tube. See error in assuming getter was blown bulb in prior Technics 840? post!! Goon..They can't be used as amps though...
The pins can usually be traced from the back. The pins between the dots are the grid and the dots are the elements in this 16 element display. Some have 16 elements for commas etc. (I missed a few grids in between below).
The cathode heater wires are usually the two end pins and the wires can be seen glowing hot with as little as 6V DC applied (-6v-0V). These are the "cathode" lower voltage points. The grid points can be soldered together then set to slightly higher voltage using a dual PSU. The anode as the highest voltage - about 12V - should show all the elements for each character block lighting in the unit if soldered together. This faulty unit has missing elements.
The black croc is the highest voltage of the dual series PSU at about +12V, the red and black crocs at each end are the low voltage heater wires cathode about -6V-0V, and the red spring clip is on the grid at 0V