Major DMX issues




I am having issues with DMX, and can't find a solution.

I have 430 dmx channels, using 17 Ray Wu Boards.

The other day I thought I had an issue with my D2 - turns out it wasn't the issue.

There are a few things occuring -

1. I have about 3 boards that are not playing the right DMX channels.I double checked and re checked all dmx addresses, but they play or repeat earlier dmx channels (like 1-26) even though it should start from channel 163. So hence the items are not playing the correct channels.

2. When I just disconnect all the dmx cables and run the dmx signal straight from the d2 to most of the control boards dmx input, the dmx signal does not flash. It will only flash if i connect it to several other control boards.

I think it may be a ground loop issue - but I am not sure how I am meant to resolve it?

I don't have a dmx terminator in yet - could this be causing an issue?

I am not understanding why the dmx signal won't work when just plugged into one board. and I am not understanding why a few of the boards are not playing the correct dmx channels, even though the are correctly set.

Could it be the D2?

I am getting pretty desperate, because I have had to delay the start of the show by a week and at this stage can't get it to run properly.

ANy help would be appreciated.



Senior elf
Generous elf
May 6, 2010
Lithgow, NSW
Check the switches - I have had a number of them that dont work properly, so the address is not actually set correctly. Usually they fail to close one of the contacts so your address is lower than what you set.


I Have C.L.A.P and its very infectious
Global moderator
May 29, 2010
Are the channel DMX dip Switch selectable, I recall I had problems with funny channels and worked out it was a dud switch on the board. I couldnt use the board for any channel that needed switch 7 turned on.
worth checking