Repairing existing ShowXPress, Chauvet XPress512, DMX system

usb to dmx - 512 dmx channels

Repairing existing ShowXPress, Chauvet XPress512, DMX system

Postby GatorTPK » 28 November 2021, 01:30


I do camera install and computer repair. I'm new to DMX lighting. I've learned a bit in the past week since I've been tasked to get an existing DMX lighting system running again in the same place I'm adding cameras to an existing camera system I've installed. I'm using a 19 foot lift to reach the fixtures 22 feet up and only have one more night to work on it.

They already have the ShowXpress Windows software, the Chauvet Xpress 512 (USB interface to 3 Pin DMX), and a number of fixtures. I noticed a cable cut (intentionally?) about six feet away from the first fixture (Intimidator Spot 360). So I ran a new DMX cable (braided shielded with white and black internal conductors). I soldered the ground shield to pin 1, the white to pin 2 (data -), and black to pin 3 (data +), which I found unintuitive, but all the other blacks were connected that way and had red conductors to pin 2. (I used only Neutrik connectors)

I've checked the addresses on the first fixture (Intimidator Spot 360) which is set at 400 in DMX (14CH) "Running Mode DMX". The ShowXpress software has that same address as well. I even started a "New Lightshow" and added the fixture to that address. I see the bright blue power light on the Xpress512 interface and the PC light blinking. It blinks faster when I send commands from the software such a pan/tilt, etc. I even see ~1, ~2, and ~3 volts DC at the other end of the cable depending on which two pins I measure the voltage differences.

The the fixture does not respond at all! Nothing ever. I even disconnected all the other lights (by unplugging the DMX out cable) to be sure they're not causing an issue because I understand this is all digital signaling going through he DMX cable. I did unplug the Intimidator Spot 360 fixture from 110VAC power for a few seconds and it does its slow then fast pan and tilt startup routine. The fixture will move then, but never to my command with software!

Any suggestions?

Thanks in advance!
Posts: 1
Joined: 28 November 2021, 00:54

Re: Repairing existing ShowXPress, Chauvet XPress512, DMX sy

Postby Robin_D » 29 November 2021, 20:57

Easiest way to test is to get a spare XLR to XLR cable (Mic cable will do) and connect the second fixture directly to the DMX out disconnecting everything down stream. It is sometimes easiest to take the laptop and device up to the rig. If second device works, connect the downstream link and test the rest. If all OK the DMX is working, so connect to the first device. If that works your cable up to the rig is faulty.

Good luck.
Posts: 27
Joined: 13 December 2017, 17:42

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