VICON Tracking System Repair

This system tracks the position of flystick(s) and eyeglasses in VR space using some (≥ 3) high-speed (100 fps) infrared cameras, retro-reflective balls (∅ 1.2 cm), and an image processing unit called Data Station.

					 12  ╔══════╗
			╔════════════╗   ┌───╢Camera║
			║            ╟───┘   ╠══════╣
		    ┌───╢Concentrator╟───────╢Camera║
╔══════════════╗  14│	║            ╟───┐   ╠══════╣
║              ╟────┘	╚════════════╝   └───╢Camera║
║“Data Station”║  25 m		       10? m ╠══════╣
║              ╟────┐	╔════════════╗   ┌───╢Camera║
╚══════════════╝    │	║            ╟───┘   ╠══════╣
		    └───╢Concentrator╟───────╢Camera║
			║            ╟───┐   ╠══════╣
			╚════════════╝   └───╢Camera║
					     ╚══════╝

Principal wiring

All wires in between were special-built with strange, expensive, and hard-to-solder plugs.

See schematic for interface parts of Data Station and Concentrator, and text file (German) for pin assigmnents.

Camera: Infrared Illumination Repair

After some years of use, the infrared LED illumination ring goes out of work. This ring is fed with 52 V, and gets two extra control lines, possibly for shuttering and off-switching. Replacing all LEDs is done by processing the following steps:

Remove the LED illumination ring from camera by pulling an edge of the four-pin LEMO connector towards front-side.
Open the case using 2.5 mm hexagonal screwdriver
Disconnect flat cable to PCB by pulling the connector's latch upwards
Make space for applying a heating plate to the PCB's bottom side:
- Desolder two electrolytic capacitors C8 and C9
- Desolder transistor Q1 (it's for the LED current regulator)
- Remove latch of flat cable connector
Put the PCB onto a heating plate or a reversed iron, but watch not melting the flat cable connector
Remove all 66 LEDs (Type SMT780 by Epitex) while PCB is heated
Clean solder pads using solder wick
Apply (preferably low-temperature) solder paste to the 132 pads; I used bismut solder
Populate replacement LEDs; I used Osram SFH420, available at distributor Reichelt
Put the PCB onto a heating plate or a reversed iron again
Populate transistor Q1
Populate electrolytic capacitors C8 and C9
Connect flat cable, close the case, plug onto camera, enjoy.

Soldered replacement LEDs. The SFH420 have a cathode mark!

Soldering by hand is absolutely not recommended for such LEDs! Their cases melt in contact with the soldering iron, and the gaps between them are quite small, at least for the inner ring.

Replacing only defective LEDs is not recommended.

Concentrator Repair

There was some lightning strike, and some chips were destroyed. The high-speed video data transfer is mostly done using special symmetric transmission line transmitters and receivers by Maxim, no chance to get spare parts! (I have some now, after scrapping)

Therefore, the one-and-only repair was to interchange chips so four (here: all) cameras would still run.

Data Station Repair

Same as Concentrator Repair.