LED Lights Flashing?

[Tyler]

We recently bought and now use 4 American DJ LED fixtures. They are DMX controlled, but randomly flash when they aren't being used (still have power running to them and still connected in the DMX chain.

I use 1 string of XLR cables going through a few other intelligent lights. I also have a DXM terminator. Could the terminator be the problem if it isn't working right or is it the configuration of the lights not right?

Thanks,
Tyler

[farmerjo1111]

I would double check the Terminator and check and see if they still flash when they are not plugged into the board. The light board could be sending out bad information on the DMX line.

[Footer]

It could be cross talk/interfearacne of the line. Make sure that your terminator is made correctly (pins 2/3 120 or 100 ohm resistor) and that all your cables are legit DMX cable, not microphone cable.

[Tyler]

I'll have to check the terminator when I get in later. What is the difference with DML cables and microphone cables? Aren't DMX cables just xlr cables which are used for microphones?

[Dustincoc]

XLM only refers to the actual connector on the end of the cable. Both DMX and Microphones use XLR Connectors. Cables used for DMX should be of a higher quality cable, usually a twisted pair, shielded cable to prevent interference and cancel out any that does occur. Microphone cable should also use sheilded cable, but often unshielded cable is used due to cost concerns. Microphone cables are also easily confused with DMX cables and can be swapped in a pinch but the problems you experiencing are one reason that its not ideal.

[Van]

Somebody can look it up, I used to know it but I've slept since then. The original spec for DMX cable was a Belden 5432 ,I believe, The specs are specific and for a reason. Mic cable is not a substitute for DMX line. Thats sort of like wirring an home computer network with zip-cord , (huh ? You cain't do that there either ? )

There's another post discussing termination, do a search for termination to find it since you can't search for DMX. I think you will find several useful insights as to what might be the cause of you problem. Personally I'd gues a capacitence build up in the shield of the mic cable that was intermittantly discharging cause the lights to flicker, even though they were not plugged in. Remember, a wire, sitting all by itself doing nothing what so ever can build up a charge from bombardment by radio waves, <and alien mind beams>. Enough of a charge that you can actually detect it with a meter, or if you're board hook up a cyrstal diode and a coil and you can listen to the radio on it. The point I'm making here is, yes there is one, Read the specs there really is a reason they are written. Terminate everything on a dmx line that is not self terminating. Double check solder connections on the XLR's double check pins on the XLR's, It's a digital world and and as My very first Programming class taught me, on a TRS-80 I might add, Garbage in garbage out, Crappy cables , crappy light, Poor maintenance, poor performance ........ Ok stopping now

Good luck ! Have Fun, that is what it's all about !.

[soundman]

I think I have used the same fixtures before, make sure you take them out of sound reactive mode.

[SHARYNF]

Some of the early units did not have the ability to support the full 512 address range for DMX. It is possible that you have something else in the same address range? If I recall these use 6 dmx channels so is it possible that you have an address set incorrectly?
Sharyn

[Tyler]

Thanks for all the help guys. I still haven't had time to go in yet and check the terminator, I may have to replace that. And we do use regular microphone cables for the most part, which may be the problem.

I'm almost positive that we don't have any other fixtures in the same dmx range, but I could have always made a mistake so again, I'll make sure to check that.

It's just weird becuase it's a random flash, almost like a jolt of power hits it and the power needs to go somewhere so it makes the light turn on very quickly. And it is all 4 led's so I know it's not a problem with the actual fixture.

[BillESC]

Mic cable is rated at 80 Ohms. True DMX cable is rated at 120 Ohms and is constructed using twisted pairs. We build our DMX cables using Duraflex cable which is also double shielded - both a braid and foil shields. Never had a problem.